As far as MMOs go my side games have always been Warframe and Guild Wars 2, though I'll have to check how compatible the new release format of the latter is with my habit of just dropping in to the game every six months or so and catching up on the content that released in the meantime.

Besides those I play a lot of co-op titles with all one of my good friends and enjoy bashing my head against all sorts of metroidvanias and puzzlers.
When the Grim Dawn expansion releases that will likely see me step away from FF for a while, too.