/catninja - does sounds but does not show the projectiles or block damage
/head - needs to be updated to work with UUID
/sit - been broken forever
/larpa - ghast moves really really slowly
/imrich - glitch
/bacon - glitch
/larpa - ghast barely moves
All the morph commands (/enderdragon, /sheep, etc) seem to be broken
/piggyback - broken
/followsnow - doesn't follow, sometimes spawns below ground
/followpoop - doesn't follow, sometimes spawns below ground
*semi broken commands*
/revert - sometimes doesn't allow a player to revert, even if they've voted with in a reasonable time-frame (ie: player votes at 10:00 AM, then an hour later at 11:00 AM something explodes/burns but they cannot revert it) the time-frame of being unable to revert seems to vary but the longest reported is ~8 hours
Ill add more but ive used up voter commands for today