In the beta (Windows), I've got Izotope rx6 plugins all working (basic functionality, but not fully operational), a few free ones from Voxengo, TDR and Marvel and some free Reaper plugins which were installed much earlier but are coming up now for first time in Resolve. Haven't tried those.
You want 64bit VST2 plugins; 32bit and VST3 don't work with earlier versions and presumably don't with V14 either.