All actions in this game generate enmity, but to what degree varies. Buffs like Stoneskin, Eye for an Eye, and Protect would generate 1 enmity point on an engaged mob. If a tank can't reestablish enmity from a "buff" then they are probably the worst tank in the game. The same applies to debuffs like Virus and Foe's Requiem. They only add 1 point of enmity to the list so it's not THAT huge of a deal (again, unless your tank is horribad). Regardless of how good they are, if a tank can't wait 3 seconds for buffs and pulls while they are being casted, he is a shitty tank.

Heals and attacks generate a lot more enmity based on how much of an effect they have (amount done).