Greetings, all!

Just as the title says - what abilities, when used by a player character class, make that class automatically tier 2 or better?

I'm not counting loops here. Being able to infinitely use an ability either has no major effect on tier (like a Warlock's invocations or dealing infinite damage against something with finite HP) or makes someone effectively unstoppable (using gate to call a Solar then bringing in an arbitrary amount more Solars that round).