I borrowed everything below from the retribution wiki. I assume most of it's informations are true, even if it's contradictory with in game description who sometimes outright lie to you because of some old patch that changed how said equipement work ect... If in game you experience something that contradicts what I've found, feel free to notify me. and of course, if you know something I don't, feel free to share too. And sorry by advance for akward grammar or typos, the following is just a collection of short notes I made while reading the wiki.

-All heroes units, melee units, tactical squad, scouts and chaos space marines receive -40 % melee damage

-Mines supress infantry and significantly slow vehicules. You probably know if you use mines from time to time but mines are rare

-Smoke grenades decrease received and given ranged damage by 80 % and more importantly lowers supression by 90 %.

--Don't forget that partialy revealed infiltrated units receive -20 % ranged damage, and it fully stacks with cover.

-For The emperor (FC), in addition of increasing ranged damage, decrease received melee damaged (-25%), wich means it can be used to partialy counteract the vulnerability to melee retreating units have (+30%).

-The iron halo and everything similar (when activated) grants immunity to most knockbacks

-The storm shield, in addition to its OP ability, does reduce passively the ranged damage taken by the FC (20%)

-The terminator commader's powerfist does hit like a powerfist, hence is great against heavily armoured targets. This is slightly more common knowledge than the rest but it's not super obvious either.

-As a consequence, lighting claws do decrease damage against armoured targets

-Continuing on terminators, regular terminators aren't bad at close combat either (34 heavy DPS per model. Thunder hammer terminators are 45 heavy melee DPS per model). They, however don't benefit from melee resistance like assault terminators.

-Most of the techmarine's weapon only increase his DPS by around 3 (from 35 DPS to 38-37 depending on the weapon.), so bolter upgrade are only good for their ability and melta gun for the change in damage type (only worth it against vehicule and super heavy infantry). It's also the case for the plasma but it's ability is to literaly double its DPS so…

-The teleporter relay's aura increase regeneration by 1.5HP/second where as the stronghold is 1 %HP/second (2.5 % for commanders), wich means the relay is trash to heal anything other than a scout. For instance a tactical marine (330 HP) heals 3.3HP/sec at the HQ, wich mean the relay heals them 2 times slower, so don't even think about healing your ASM or terminators there.

-The techmarine's grenade does serious damage to eldar's deployable shields and burns 100 energy from all target in its area of effect. Insanely situational

-ASM are actualy fairly bad at melee against other melee units without their sergent. I've seen them losing to upgraded heretics.

-Dreadnoughts, when upgraded with the assault canon, are still fairly acceptable in melee against vehicule. It still wins against an upgraded deff dread.

-Units around a land raider are immune to supression and receive -25 % ranged damage. They also heal 1 %HP/seconde (similar to the stronghold.)

-The « Quickening » of the librarian reduce received ranged damage by an impressive 90 %.

- « Force barrier » does ability knockback, wich means it affect terminators and other infantry unit that are usualy immune to knockbacks

-Scout's bolter do about as much damage as a shoota boy (7.58 vs 7 DPS). Tha's how bad they are.

-Shotguns, on the other hands, do about as much damage as a tact bolter (14.67 vs 14.58 DPS). Shotguns are good.

-The sergent's pistol of tactical marine has the DPS of a bolter. Considering the sergent cost as much in req as a regular tactical marine, it's always a good idea to buy him if you don't need energy.

-Tactical marine capture 50 % faster, in case some people didn't know.

- « Call da Boyz », in addition to allowing rienforcements increase the speed and the damage of ALL of you infantry, not just in the rienforcement radius.

-The rienforcement range of « Call da boyz » is actualy fairly large (50 game units. The range of a heavy bolter is 49)

-The mek's ranged damage is fairly bad (24.5 DPS. The Knob shoota is 35 DPS). The big shoota only brings him to the level of other heroes. This is probably done to compensate the teleportation ability (as the WSE has similar base damage), so always teleport you mek to flank the enemy, even for just shooting.

-His heavy weapons also deals less damage compared to the loota's equivalent for the same reason.

-The waaagh ! Banner knockbacks and stun enemies that are too close upon activation. It makes it an alright counter to jump infantry and other annoying melee units.

-The waagh ! Banner has a larger detection range than normal, but still much smaller than regular detectors as the banner has a trash sight radius to begin with.

-'Ave a taste from the battery pack heals 400 health per model,wich is enough to fully heal most space marine units.

-The big shoota of the warboss hasn't a better DPS than other commander's pistols. The range is however quite impressive (49, same as a heavy bolter). The enhanced kustom shoota brings the boss to mek level in terms of DPS. (still bad but you can now hope to kill something)

-The deff dread big shootas, despite being, well big shottas are fairly bad. The burnas are alright tho.

-The kommandos actualy have a really good ranged DPS (16.92 DPS, tact are 14.58 DPS)

-The nobs's huge choppas are melee heavy like the hammers with a similar DPS (33.33 vs 36.67), despite the icon above the nob suggering a change. The appeal of the hammers are the fact they deal more damage every concecutive hit, wich is only worth it against really tanky stuff like super heavy vehicule or infantry, considering the hammer cost 100/60

-The burnaz, like the tabletop, change the melee type of the burna boyz to power melee. (around +30% damage against heavy infantry). Fairly neglible but a nice detail.

-The sluggas probably have the most awful shooting of the game with an impressive 0.49 ranged DPS per model.

-Guide is percentage based, wich means rangers and D canon gain a truly absurd range.

-Units around a warlock or a seer council get increased energy regeneration

-The warlock's destructor is grenade damage type, wich means it does full damage damage to retreating units and units in cover.

-Distort field negate all ranged damage taken by a retreating unit

-Warlock's cloaking shroud reduce received ranged damage and supression in addition to the regular infiltration bonuses

-The merciless blade description says it increases the warlock ranged damage (wich is true) but it's quite negligible compared to the massive increase in melee damage it gives.

-As stated in the ork part, the WSE does less damage than regular shooting heroes, wich can be returned to « normal » with the entangling web upgrade or the imporved targeters. Unlike the mek, he also has decent melee damage for a ranged hero

-During the channeling of group teleport, all affected unit are immune to knockback for some reason.

-The autarch aura reduces ranged damage taken by 10 %

-The autarch jump, in adition to its heals, also increases speed and damage for units around

-The Avatar aura is -30 % ranged damage taken +30 % more damage. It's good.

-The banshee's exarch exutionner is quite good against vehicule for a sergent (51.43 heavy DPS. For reference, the farseer signing spear is about 70DPS and the FC with powerfist is 85DPS)

-Base synapse decrease received damage (even melee) and supression by 20 %

-Lictor's scything talons don't do more damage than his other equipement, rendering them utterly useless.

-Lictor's lone hunter activation range is actualy fairly low, about as much as the range of your average ranged unit so if for some reason the lictor is alone in close combat, he will probably benefit from it.

-Ravener's hive node (that thing that nobody ever build) decrease ranged damage (done and received) akin to a smoke grenade but grants a straight up immunity to supression and slow enemy trapped the cloud while dealing a bit of damage.

-Catalyst increase damage by a 100 % (double the damage). Godlike to finish things in melee.

-The Carnifex's strangeler is actualy plasma cannon type, making it really good against heavy infantry unlike its warrior counterpart

-The Carnifex's venom canon has a 100 % moving accuracy.

-Carnifex's melee damage is only reduced by 10 % if he has a ranged weapon, he remains quite deadly against tanks.

-Ripper swarm gain a HP and damage boost when you upgrade to next tier, leaving them relevant in the late game.

-The regular lictor has an absolutly incredible DPS for something of it's size (93.75 heavy DPS , the carnifex or the dreadnought is 100 heavy DPS + the splash damage, if you don't realise how much that represents.) This also means the lictor is actualy an excellent anti vehicule unit.

-The termagaunts do such bad damage without upgrade that you might as well melee with them as they have an equivalent DPS. Please buy their upgrade.

-The tyrant guard damage is heavy type, combined with his giant healthpool, he is actualy decent against walkers.

-On the other hand, his armor type is actualy super heavy infantry and not vehicule, wich renders him vulnerable to things that vehicule do not normaly fear while still being targetable by anti vehicule abilities. His armor type changes to vehicule when shieldwall is active.

-Warriors keep their full melee power when upgraded with a strangler

-The zoanthrope aura becomes increasingly powerful with levels. Base level is x4 health regen for allied units, max level is x70, and yes I typed that correctly.

-The combi flamer increases the damage of the bolter part, making the CL doing fairly decent ranged damage. And as a terminator, he has a 100 % accuracy on the move, wich can make him okay at punishing fleeing cowards.

-The maul and the claws have the same DPS and the same damage type, despite the claws changing the icon above the lord and the maul not doing so. Im fairly skeptical about this one, as the claws cost way more than the maul, so if let me know if someone tested this.

-The harness of rage doesn't increase damage, but instead restore 5 energy for each hit plus 150 health and +1 hp/sec regen

-The plague champion's bile flamer decreases the speed and damage of those affected by it.

-Zombies keep their abilities, wich can lead to some unexpected combos, most notably with jump infantry with each zombie knockbacking the hell out of the enemy gunline.

-The bloodcrusher has actualy fairly massive damage (93 heavy DPS)

-A dreadnought under bloodrage keeps targeting the unit you initialy ordered it to attack giving you some control over it. Blood rage also decrease received damage by 50 %, wich is pretty massive.

-Noises and havocs, like CSM, have a good melee DPS, but don't forget they don't have melee resistance. Funnily, the khorne mark (autocanon) does increase melee damage of the havocs.

-Veneration heals the bloodcrusher faster than regular repair (12hp/seconde vs 10hp/second)

-Here's what the mark of tzeentch really do to CSM :
-Slightly better base damage (13 to 18)
-Damage against heavy infantry -30 % to +25 %
-Damage to super heavy infantry -70 % to +0 % (base damage)
-Damage against vehicules -98 % to -90 % (that's a +400 % damage increase)
-Other unimportant modifiers
-A bolter for the champion

-Unlike loyalists, the aspiring champion's pistol doesn't have the DPS of a bolter. (unless he gets one through tzeentch)

-The great unclean one vomit counts as plasma canon damage, wich means it's actualy pretty decent against vehicules.

-The inquisitor's holy pyre (the brasero ability) can detect infilitrated units. Quite fitting.

-Lord general's « Fire on my target ! » (the sniper ability) is precentage based, making it really good to buff lascanon/autcanon or hellgun stormtroopers.

-The banewolf passively slows units by a whooping 40 % in addition to it's ability.

-Catachan's melee is better than banshees. I'm not even kidding.

-Honestly the IG is pretty straightforward. There isn't much to say