I guess that, with all the different races in the game, there will be specific items for each of them, won't they? If so, here are a few ideas:
IG:
- Carapace armour: better armour (ofc)
- Macharius Cross: gives an aura that increases movement and attack speed of nearby allied units.
- Honorifica Imperialis: increases damage, life points, speed... everything
- Hellgun: faster and better attack
- Longlas: sniper laser rifle which gives an powerful sniper shot ability
Eldar:
- Warp jump generator: gives the teleport ability
- Banshee mask: gives the banshee howl ability
- Fusion rifle: gives an anti-tank ability
- Reaper weapon: gives an area anti-infantry ability
Space Marine:
- Cross Terminatus: something like the Honorifica Imperialis for IG
- Nartecium: gives an heal ability
- Storm bolter: raises attack speed and damage
Chaos Space marine:
- Mark of Khorne: better damage
- Mark of Nurgle: better HP
- Mark of Slaanesh: better speed
- Mark of Tzeench: better energy (mana)
I can't think of anything else right now, I may post something different in the next times. =)
