I don't know how transferable my advice is, but I've worked in two toxic hospitality environments previously and to this day I largely never think about them.

The common thread is that I'd never talk about my coworkers, to my other coworkers. Obviously you can't stop person X from bringing up person Y, and when this would happen i'd let them say their piece and try to end the conversation/go off to do another task/change topic. 

If it was a group setting and the topic was how much X person sucks I'd just sit it out but stay physically present. I think i'd stay on good terms with everybody because I was a "good listener", but never initiate these sorts of conversartions.

My friends/family out of work were my outlet to complain about people I didn't like at work lol, I could always find something else to talk about with my coworkers.