So since we can’t share any gear your could make some individual grenade buffs that improve them and make them more versatile.
Add a new item slot and sell grenade booster items.
Sharpshooter
Grenade regen
Aoe
Knock back distance
Bleed stacks
Zealot
Burn stacks
Duration
Bleed stacks
Skull braker
More penetrative so you can bowl over every it hits but stops on ogryns, maulers and mutants
Weak spot damage
Bounce
Brain burst.
I honestly don’t know how to balance it since it would probably get real OP in malice and still bad in heresy + if you just made charge speed or warp res or more damage.
But interesting ones would ones that give you utility so.
aoe knock down explosion
fire lightings that stun out the neck stump.
Warp fire explosion that’s like a fire nade for a short time.
Mind control while channeling so they friendly fire each other and for a few seconds after if they live/when they live since it doesn’t kill much on high difficulty.
Is this gonna be balanced probably not but it would be cool.