Commands that MUST be accessible while in combat:

*/ct - to see when you are out of combat
*/feed - to feed you
*/ext - to extinguish you
*/tpaccept - to accept a teleport request
*/invsee - see a players's inventory
* /tpa - teleports to a player
* /msg - private message's a player
* /back - teleports you back to your previous location

*Pretty much the only command that shouldn't be removed is /enderchest because people tend to abuse it when close to death*