I use provoke, convalescence, featherfoot, mantra and flash. The first two are no-brainers. Here is why I use the other 3:

Featherfoot: I stack this in a macro with Foresight and Bloodbath. If you have a few adds, the evasion might just make a difference. More mobs hitting you, higher chance for the dodge proc.

Mantra: 5% might not sound like much, but if you use it at the right time, I think it is great. Levi "big move", Titan Tumults, T6 Raffy spit, T7 single tanking, T8 defense tower explosion, brayflox. IMO, it is better than the chance of not getting a crit hit from Awareness.

Flash: Just a utility thing. I use it in Bray when I run past mobs during big pulls. I use it when Berserk has caused Pacification. I've used it in T7 if an add spawns and I have to handle voice (Provoke + Flash when it comes over). I think it has more utility possibility than any other possible cross class ability that I'm not already using.