I want a Diver Beetle themed Pokemon:
https://en.wikipedia.org/wiki/Dytiscidae
Why? Because I want to see a water/bug type Pokemon that stays a water/bug type Pokemon!
I want to see a poison type legendary, you can base it off of volcanic smoke, or just in general smog for all care, if the former happens it'll most likely be a poison/fire type.
Also I want a Chimera themed Pokemon, it could be a slow Pokemon that can function well as either a physical attacker or special attacker or better yet mix, it would probably wind up being a dark/poison or dark/fire type or for that matter the poison/fire type mix I mentioned just a second ago.
Finally I also wish to see a Manticore themed Pokemon, it could serve as a brutal physical attacker type I could see it being Dark/Poison without a doubt