What resistances should I get?

[Savior]

So do Time Diablo & Lich have conviction you just can't see it? Any other bosses that have this?

I'm pretty sure those two specific bosses Time Diablo and Lich King just have very strong attacks compared to most bosses.
To reduce the damage they deal to you even further you would need cold or fire absorb.

Edit: And I'm not sure if any bosses have conviction, I just always keep my res high to prepare myself just in case one of them might have it lol.

Or if they have any type of skill that can lower my resists somehow, better safe than sorry.