New activators suggestions:
PLAYER_HIT //hitting a player
PLAYER_CLICK //right clicking on a player
ENDERTP //activated after tped using an enderpearl
SNOWBALL //throwing snowballs
SNOWBALL _HIT //hit a mob or player with a snowball
SNOWBALL_HITSELF //when you got hit by a snowball
JUMP //...
LAND //landing after jumping from a defined <height>
EAT //...
DRINK //...
STARE // looking on a block/player/mob/location/refion
ENTER_WATER //...
ENTER_LAVA //...
BREED //breeding mobs
FEED //feeding mobs
ENTER_BOAT //...
ENTER_MINECART //...
CRAFT //with abilllity to choose what item/block
SMELT //same as above
HOLD_ITEM //holding an item
SPRINT //...
CHAT //when said something specific in chat
BLOCK_PLACE //...
BLOCK_BREAK //...
BLOCK_CLICK //right click on a block
ENCHANT // with <level>
BOW_AIM // holding right click with a bow
BOW_SHOOT //...
BOW_HIT //...
BOW_HITSELF //got hit by an arrow
ITEM_DROP //...


Flags:
Weather
Class or Race (with RacesAndClasses plugin)

Aaaaaaaaaaaaand im out of ideas. :) I hope you add most of them.