I've logged mabye 4k rev kills total. I kill all revs that are around aside from the dragon which i only kill if I take a brace or two. I write down the item and what I got it from every time.
So far I have these items in my kill log:
Dragon: zamorak stat, vesta chainbody, dragon mace, 5 (regular) d scims (I have not killed more than 50 dragons total so my items from him ar ea bit lower than average)
knight: arma stat x2, bronzed dragon claw x2, corrupt dmed, serin stat, corrupt d spear, (Gotten a lvl 3 (hard) clue aswell.)
Dbeast: Zamorak stat, arma totem x4, corrupt dskirt x2, corrupt dmed, corrupt vesta spear, corrupt dchain, broken statue headress, guthix brazier. (10+ 120 death rune drops)
Ork: corrupt morg javs, corrupt throw axes, saradomin stat, corrupt dscim x3, corrupt drag dagger. (10+ regular drag daggers)
Demon: Corrupt drag sq x2, corrupt stat warhammer, corrupt zurial top, ancient stat. (a lot of rune longs, probably 25+)
hellhound: corrupt d spear, corrupt vesta spear, bandos stat, broken statue headress, third age vase.
cyclops: corrupt drag dagger, morrigan's coif, armadyl totem x2, broken statue headress x5, corrupt d spear.
wearwolf: saradomin statue, guthix brazier, corrupt dscim x2
hobgoblin: corrupt dscim, corrupt dchain, armadyl totem.
pyrefiend: vesta hcain body, corrupt dmed, corrupt dspear, corrupt dchain x2, corrupt d mace x4, armadyl totem x2, saradomin stat, stat full helm , corrupt vesta long, corrupt morigan's coif.
ice fiend: stat full helm, bronzed dragon claw, brawlers (melee)
Goblin lvl 30: corrupt d med, corrupt zuriel top, armadyl stat.
goblin lvl 22: armadyl stat, bronzed dclaw, third age vase.
goblin lvl 15: (mage) brawlers, broken statue headress.
imp: nothing. (just coins occationally)
Oddly enough, my top item dropping Rev is the Pyrefiend lvl 52.
I do use jennica's ring every trip. although I've done trips without it and my items/trip yield didn't change noticably.
Along with everyone else, I can have a trip where I get 5+ items, and then 3 trips with nothing at all. I believe the higher level revs do drop items more often, but I think what item is dropped is purely random. The imp and dragon can drop all the same items, just at different rates.