There is a lot of things you might ask about, if they can implement without interrupt mechanic (not a D&D term, but basically: decision is to be made outside your normal turn), but reactions are the most prominent.

Other stuff include Lucky feat & Portent (lvl 2 divination wizard), deciding if you want to do AoO or keep reaction for something else, Divine Smite during AoO...

Last edited by mg666; 17/11/20 03:55 PM.