Here's a pretty fun team I made that I've been having success with. It's built around the classic M-Mawile + Greninja offensive core.
M-Mawile is SD with Thunder Punch which is my favourite set rn, as you don't have to mess around with Toxapex or Celesteela. The 4 Attack set could also work, but I prefer a set with priority because this things speed is so disappointing.
Ash-Greninja is Waterium Z, I prefer this set because it's easier to set up Spikes with it. If your opponent has something like Protect Heatran and you go for Spike you aren't forced out afterwards which is cool. Alot of people don't expect Waterium so it catches them off guard, giving you a free Ash.
Next I added Defog Gliscor, which is basically the Heatran answer (except not really bc Modest Z still bops lol) U-turn is helpful to keep momentum and bring in Mawile or Gren.
Scarf Koko was the next slot. Its basically the anti-cheese mon as it helps vs rain, Gyarados, Zygarde etc. It's also a flying resist which is cool vs Torn. U-turn on Bulu/Tang to bring in Mawile, really simple.
I still wanted a bulky grass but also a rocker. Tang and Bulu weren't options so I went Ferro. Power Whip because being walled by Gren on this team would be trash, Thunder Wave is pretty cool to help against broken Heatran and the very occasional Volcarona.
From here I was still pretty Zygarde weak, I was also weak to fighting types like M-Medi. So the last slot is Mew. Taunt is a pretty cool tech which stops Ferro, Clef, Steela and Pex from using every status move/hazard in the game. I didn't have a Heatran or any fire coverage so M-Sciz was really annoying, even if I burned it, it could setup and be a pain. So I decided for Fire Coverage on Mew, Fire Blast has a chance to OHKO M-Scizor from full and is 100% after rocks but Flamethrower can work aswell.