High Elves
Power Fist Gloves:
Grants +[x + (y * str)] damage for a period of time.
Cooldown decreases and damage gains a minor increase per level.
Shroud Cape:
Temporary invisibility and armor.
Armor duration increases and cooldown duration decreases per level.
United Creep
Summoning Stone:
Summons a unit based on the casting hero, with a limit of [item level] at a time.
Cooldown decreases duration per level.
Ethereal Chain:
Allows hero to "bind to a target" (target must be in a certain range), later being able to warp to it via targeting it.
Note: Casting on a different target will result in changing bind to said target, unless out of range, which will do nothing.
Cooldown and cast time will decrease per level.
Grim Brigade
Grim Skull:
Grants X health every time necromancy is cast.
Heal amount increases per level.
Cursed Jewel:
Traps target in a bone prison (basically web).
Cooldown duration decreases every level.
That's basically all the ideas I got for now. I think adding racial items would increase racial personalization. As well as possibly normal play encouragement.