The Inquisitor and Grey Knight hero have a large array of wargear they can be equipped with as they have access to the Imperium's highest quality weaponry and armor. The Daemonhunters often stock their armories full of equipment made to better battle the daemon and Chaos, so much of the things listed here will have that sort of theme. I'll do a brief summary of those I think shine and those I think are not worth taking. While a Justicar and Inquisitorial Stormtrooper Sergeant can access many of these items, I'll only mention it when it seems necessary.

• Anointed Weapon: An anointed weapon is akin to a poisoned power weapon when fighting Daemons. A power weapon with this quality automatically wounds on a 4+ (unless normally you would need to roll lower) and gives an Armor Penetration of 2D6 + Strength against possessed vehicles. Only one per army. Counts as a power weapon in all situations.
  
  Not great, to be honest. While it is very handy against Daemon armies, chances are you won't be building a list to fight them and only them. Plus, it costs 20 pts and doesn't remove their invulnerable save. However, if you are building a list to squash Daemons, consider this for your favorite close-combat HQ. This does still count as a power weapon when not fighting Daemons, and is not an upgrade to another weapon.
  
  
• Bionics: Bionics allow you to return to the battlefield after falling. After being killed, put it on its side instead of removing it. Next turn, roll a D6. On a 6, the model is stood back up with 1 wound and continues fighting. Else, it is removed.
  
  Quite the different piece of wargear. Giving a mini We Will Be Back roll, this gives you a chance to have your HQ keep fighting after dying only for 10 points. In addition, this can be put on a Justicar or Sergeant so you can hypothetically come back from the dead and contest/score an objective. However, it is too unlikely to rely on. It's cool, but it is too random and unlikely. Fun, but not too strong.
  
  
• Chainfist: A power fist that rolls 2D6 for armor penetration.
  
  The chainfist, a bit of a standard for 40k. Nothing special here, but I can personally recommend this if you want to have your Inquisitor in terminator armor to have the ability to bash open vehicles, including Land Raiders. It is quite expensive at 30 pts., however, so you might want to look elsewhere for that option.
  
  
• Combi-weapons: A combination of a boltgun and a flamer, grenade launcher, plasma gun, metlagun, or needle pistol. The boltgun may be fired any number of times but the other weapon only once.
  
  
  Something I would like to playtest a bit more personally. I've put the combi-melta on an Inquisitor and it did do something small, but the one shot is a bit little to rely on. Either way, I think the comb-meltagun and combi-plasma gun are the only weapons worth considering and I've been thinking about putting the melta variation on my Justicars, but I would lose the Storm Bolter (and thus an attack in close-combat/shooting beforehand) as the boltgun is Rapid Firing, not allowing an assault after firing and at 15 pts., these upgrades aren't the cheapest thing. Still, it is one of the many options for anti-tank on an Inquisitor. Upon further reading, however, it seems Justicars may not be able to use combi-weapons. I'll have to look further into that, but it seems like they are off limits due to a line just above the armory list.
  
  
• Daemonhammer: A legendary Thunder Hammer that strikes in initiative order when fighting a Daemon. Limited one per army.
  
  A better Thunder Hammer when fighting Daemons. However, you do spend an additional 5 pts. on this, which could be spent on grenades, extra armor, and smoke launchers/searchlights and give a benefit more often. It is excellent when you do go against that Daemon foe. But with a generally lowish initiative, it won't see use much even against Daemons.
  
  
• Emperor's Tarot: These cards are consulted by Inquisitors, attempting to reveal the future. Both players roll a dice before rolling for deployment. If they roll differently, the Daemonhunter gets +1 on the "initiative roll" (the roll to see who goes first). If the rolls are the same, that player gets -1 to his roll instead. One per army.
  
  This can be considered the strongest piece of wargear in the list, especially by Imperial Guard players. This is a pretty big increase in the chance of going first, but it can be kind of confusing. Before you roll to see who goes first, both players roll a die. If the numbers are not the same, the employer of this gets +1 to his initiative roll. If "doubles" are rolled (1 and a 1, 2 and a 2, etc.), then that player gets -1. This is separate from the roll to see who goes first and you apply your modifier here. If you are planning on Alpha Striking, look at this wargear. There is math behind this, but I believe your chance to go first is a 57% chance with this wargear. Correct me if I'm wrong.
  
  
• Eviscerator: A chainfist that must be used in two-hands but does not require terminator army.
  
  See chainfist, but this does not require terminator armor. However, it is still hefty at 25 pts. A bit better than the chainfist for an Inquisitor, but only if you forego terminator armor.
  
  
• Force Weapon: This is a power weapon that upon successfully landing an unsaved wound, the wielder may attempt to slay one of the wounded opponents out-right with a psychic test. This counts as your psychic test for the turn and can only be attempted once, no matter how many wounds were inflicted.
  
  Due to the wording, this is above your standard Force Weapon (see the main rulebook for more information). This is because it ignores Eternal Warrior under current rules, allowing you to kill your opponent with or without it. A bit cheesy, but at 40 pts., I don't recommend this weapon. However, your Grey Knight Grandmaster (if you take him) has this on his Nemesis Force Weapon, and can be applied in this manner.
  
  
• Holy Relic: This relic may be revealed at any point once per battle as long as you did not and will not move the turn it is revealed. This gives all models in your army 2D6" from the model with this relic +1 Attack for the rest of the turn. One per army.
  
  Another odd item, this could be used well. However, it costs 30 points and only lasts one turn, so one would have to make sure a large number (ten or so) models are covered by this to really get the 30 pt. cost to be effective. The variable range doesn't help, but you can at least expect this to cover the wielder's squad. I've never personally tried it as I'm tight for points, but I can see it used well in an assault heavy army. Another problem is the lack of movement on the turn it is used. I often find myself trying to only be in an assault for a turn or two and more relying on shooting and backpeddling (more on this later), so not being able to use this a turn I move kind of hurts as my units are always moving, either away or towards the enemy. I could use some more play testing on this.
  
  
• Icon of the Just: An icon that normally sits above the backpack of a Justicar, this grants the model a 4+ invulnerable save which may be used instead of an armor save.
  
  This is an invulnerable save that can be added to even Justicars. However, costing 25 pts. (the cost of a Grey Knight), I find it both too unreliable and too expensive to buy. I used to use it commonly, thinking that one invulnerable save would be a gift from the Emperor, but in a large squad it both commonly fails and sadly only covers one model. Now a 5+ or a 6+ invulnerable save would be much more reasonable if it covered the entire squad. On an Inquisitor, Terminator Armor is much more cost effective.
  
  
• Incinerator: Spewing the purest and most righteous flame, these heavy flamers burn white hot with faith and promethium. They are template weapons with a Str of 5, AP of 4, and Assault 1, not allowing cover or invulnerable saves.
  
  Incinerators are up there with Psycannon's for the best weapon in the codex. These blast away hordes and smaller squads alike, with a high strength and disallowing many saves. Costing 20 pts. may be painful, but they are well worth it when taken in Grey Knight Squads at a reduced cost. Using these against Eldar Seer councils is quite humorous, as it wounds on a 2+ or 3+, the latter if they are on a jetbike, and disallows all saves for them if they are on foot. Against hordes of enemies, you will be quite frequently seeing majority of the squad vanish before you even consider Storm Bolter fire. These weapons are all around excellent, especially when you are castling up for a defense and let the enemies get close before blasting their troops away, lowering the model count before the charge.
  
  
• Master-crafted Weapons: A master-crafted weapon is an augmentation to a weapon that allows the wielder to re-roll one failed to hit roll per turn. This can be applied to both range and melee weapons, but not grenades.
  
  Master-crafted weapons can be very helpful when put on your HQs Psycannon or Nemesis Force Weapon, but may not be applied to Incinerators. At 15 pts., they can allow you to get that extra wound in and I highly recommend it on a psycannon on a Brother-captain if you have the spare points, but with a Grandmaster save the points. Overall, a good piece of wargear to consider.
  
  
• Null Rod: This is an obsidian rod that crackles with anti-psychic energy, canceling all psychic powers used against and used by a squad with this weapon in it. This counts as a power weapon otherwise.
  
  Ah, the Null Rod. Such a fantastic piece of wargear in many situations, but may only be equipped to Inquisitors, sadly. Excellent as it does not allow those pesky Farseers to Doom you or Rune Priests to unleash storms upon you, keeps your expensive Grey Knight Terminators safe from Null Zones and allows your to tear up Harlequins who hide behind their veils. At 20 pts, it is only 5 points more than a power weapon and at the same cost as weapons such as Anointed Weapons. I strongly recommend this if you are already taking an Inquisitor with no plans for psychic powers of your own and attaching it to any squad taking the frontline who may be the target of such psychic assaults. I wouldn't stress the points if you are already taking a Psychic Hood on your Grey Knight HQ (mentioned below), but I definitely recommend this as it is one of the most powerful pieces of wargear in the book. I may end up doing an article on this single piece alone at some point, keep your eyes out.
  
  
• Psycannon: This bolt weapon fires psychically charged silver bolts with an isotope explosive, dealing devastating damage. The psycannon's suspensors allow it to be fired on the move, though it halves the range compared to a standard shot. It has a Str of 6, AP of 4, and can be fired Assault 3 with an 18" range or Heavy 3 with a 36" range and does not allow invulnerable saves.
  
  In my opinion, the best weapon in the book, followed by the Incinerator, though that changes on at times. Expensive at 30 pts., this gun is worth its weight in point cost. One of the most effective guns against infantry, one of the only options for killing tanks at a range at rear armor, and semi-effective at slowing down transports rolling forward without extra armor, these weapons shine. High strength, decent AP, large number of shots, and versatile with range and movement. Amazing, just purely amazing. I recommend taking two of these in half of your troop squads and putting one of these on your HQ/terminators. Plus, these weapons destroy Daemons without hurting you elsewhere. Again, they are versatile and flat-out interesting. Take them and enjoy them.
  
  
• Psycannon Bolts: This is an upgrade to a bolt weapon that loads the gun with the same rounds as a psycannon, lowering AP to 4 and disallowing invulnerable saves.
  
  A bit of a disappointment compared to its bigger brother, the actual psycannon. While this does lower the AP and shines fantastically against Daemons, it simply doesn't perform as well as just taking a psycannon in most situations. You are better off paying the 20 pts. (no matter how ridiculous that sounds) for a Psycannon for the extra shots and higher strength with the same effect.
  
  
• Psychic Hood: These hoods allow you to nullify an opponent's psyker's power. Declare you are using this after an opponent successfully makes a psychic test, but before the power has had an effect. Both players roll a D6 and add their Leadership value to the score. If the Daemonhunter's score is higher, the power is nullified and the power does not do anything. Otherwise, it continues as normal. You may use this each time an opponent uses a power.
  
  Simply amazing if the opponent has a psyker. You almost have to include one of these on your Grey Knight Hero or Inquisitor Lord, as it outshines other hoods in one way. This has an infinite range. Most hoods have a 24" range, this does not. Whenever you here "psychic test/power" try to remember to use this hood. For 20 pts, this is almost necessary as it may be used on beneficial powers, while the Aegis may not. Plus, you can cover your troop squads with an additional point of Leadership when they are targeted, as your hero has a higher Ld. value.
  
  
• Refractor Shield: A piece of equipment that gives the model a 5+ invulnerable save.
  
  The icon of the just's little brother, this costs 10 less points but only produces a 5+ invulnerable save. While it can be some filler points on a Justicar, the terminator armor simply outshines it when looking at an Inquisitor. Useful in some situations, such as when you put their wielder in a rhino, but is simply too expensive. See the Icon of the just for more information.
  
  
• Sacred Incense: A brazier burning with incense that carries the Emperor's holy grace which lowers all Chaos models initiative value in the assault with a model equipped with this by one. One per army.
  
  Another one of those "Daemons only" kind of things. This, though, I assume would work against Chaos Space Marines. Costing 10 pts., this can really help in those situations where you are going against Khorne Berzerkers or other "assaulty" Chaos Space Marines and Daemons, but again has no versatility. Not worth taking in most situations, but if you building against a certain Chaos list don't forget about this.
  
  
• Storm Shield: A shield that gives the wielder a 4+ invulnerable save in close combat against one model (a bit of vagueness here), but does nothing for the wielder against shooting attacks or other models. Does not count as another close combat weapon.
  
  Storm Shields are amazing for "Codex" marines (using the original Codex: Space Marines), Blood Angels, and Space Wolves, but kind of sucks for the other three Space Marine chapters (Dark Angels, Black Templars, and Grey Knights), but especially Grey Knights. Current marines get a 3+ invulnerable save against all attacks, but older ones get a 4+ invulnerable in close combat only. To add salt to the wound, Grey Knights show their age by only having this apply to one model. Either way, it has saved that model in one or two situations, so if you are using one don't forget about it. You could ask your opponent to boost this to the 4+ invulnerable in close combat against any attackers or even compromise for a 3+ in all the assault only or shoot for gold with a 3+ in all situations, but they might ask you to reduce your Psychic Hood range at the same time.
  
  
• Targeter: Models equipped with this may premeasure before firing in the Shooting phase. "Guess" range weapons may not be fired after measuring this. (Guess range weapons are now barrage weapons)
  
  An amazing piece of wargear. For one point, it allows you to premeasure. If you have a couple extra points (which you will), throw on one of these on your Justicars or some frag grenades/melta bombs. You can try to get some better estimations on other squads by having a definite range too, but ignoring this it is still a good upgrade, especially for 1 pt.
  
  
• Thunder Hammer: Thunder Hammers are power fists that release a wave of energy when they hit an opponent. Any models wounded but not killed by this weapon may not attack until the end of the next Assault phase. Vehicles struck (hit, not necessarily penetrated or glanced) by this weapon suffer a 'crew shaken' result in addition to any other results they take.
  
  At 25 pts., this weapon is the same price as a power fist for Daemonhunters. I can't tell you why you would take a power fist over one of these, but... let's ignore that. A bit expensive, I wouldn't recommend buying it on anything really. However, you can get these for free (losing your Storm Bolter and Power weapon) on terminators, and they really can help. I often take one of these in my squads as it adds some anti-tank power. As a bonus, normal thunder hammers reduce your opponents initiative to one on an unsaved wound. These cause any model wounded by it (it implies unsaved with older wording and the such) cannot attack at all until the end of the next assault phase(which can lock a model out of attacking). Plus, it automatically shakes vehicles if they hit, not needing a glance or penetration. These come with a Storm Shield with terminators and brings your strength to 8 as opposed to 6, helping with tanks as mentioned.
  
  
• Unguents of Warding: These ointments are used to ward off psychic energies from the Daemonhunter. The character and their squad benefit from a 4+ save against the effects of any and every psychic power used against them. If the save is passed, the power does nothing.
  
  A bit of extra psychic defense, if you feel you need it. These gives you a save which can be taken after a psychic hood roll and in addition to a normal armor save/invulnerable save if the attack is one that allows for one. At 10 pts., it could bother psyker heavy opponents but it is a bit overkill in most scenarios. Again, if you are building a list for a specific opponent's list, this is something to look at. Otherwise, ignore it and fill your points with targeters, extra armor, and grenades or whatever else you can.
  
  
• Grenades: Frag grenades allow you to ignore the negative initiative effect from assault over/through cover, while krak grenades are useful at piercing enemy armor and melta-bombs even more so.
  
  Grenades can be used as a point filler. You can read more about these in the main rulebook if needed, but frag grenades are only good for assaulting over cover, which is useful for 1 pt., while meltabombs give you one attack with a Strength of 8 and an armor penetration of 2D6 against vehicles. Taking meltabombs/frag grenades on a Justicar can be helpful, and I especially recommend meltabombs if you plan on assaulting enemy vehicles. Take note that these are only equipped on the Justicar himself and have (sadly) no effect on the rest of the squad. Point fillers but nothing more for the most part. (Krak grenades offer little benefit to a Grey Knight squad as they have an equal strength and more attacks).