Tbh it's not what poke are in the meta.. It's what Pokemon go good as a team. To find this out I'd find out what Pokemon are obtainable in pro, go to showdown/battle damage calculator make some teams test them out. Then when you come up withsome good teams..friendly battle a few people with different teams so you know the pros and cons about your team and try to tweak them a bit. This may sound like a bit of work but in fact I did this for 2 days and came up with a few good pvp teams. I manage to hit the top 10 every season in yellow so far with that idea. Well this is just a suggestion and I hope it helps you! Good luck <3