Porygon2: A+ -> S tier
Extremely high bulk and utility, huge movepool, respectable SpA, often gets free Download +1s right off the bat due to Kartana/Koko popularity, impossible to OHKO and is the best TR user in a TR favoured format.
*Also doesn't take up an item slot.*
I don't understand why you'd use Wartortle over Togekiss. Togekiss gets guaranteed FM vs all those Fake out users, has better stats, better support moves (Tailwind/Thunder Wave/+) and it can actually use real items.