Theres still quit a few bug, such as unavailable shinies being unplayable (RIP shiny zygarde, best espeed revenge killer and best colors ever).
About regular zygarde, i have really been appreciating protect on it, as it has really few checks on offense (whichis the only playstyle viable rn) bar weavile, which it can pass through thanks to this. i will try to get some replays, but i have used protect on almost every game due to how prevalent weavile is, and because people will just fodder their mon thinking weavile will revenge, letting you setup.
An other mon that might have a lot of potential as a sweeper is gyarados, as it resists all espeeds, and has nearly perfect coverage with earthquake+ aerilate return.
I have also found skarmory to remain a great wall, as it can check zygarde, scizor, weavile,... rocky helmet is really nice due to how common return and espeed are. Finally it sets up rocks, which are great against many common threats such as entei, noivern, weavile...
However, i am still looking for a good hazard setter that is not either too passive or a suicide lead