Placing decks in tiers is really, really hard. I have no opinions on what should be T1,2,3,4, etc. The metagame shifts very, very rapidly, and organizing all these decks for new ones to come out and make the others obsolete, and with decks getting new tools all the time, it's really a lost cause. With a lot of people, each with their own opinions with so, so, so many decks, it's chaotic to organize them all into a neat list. Is it possible? For older/aged metagames, yes. Look at older formats and the answers become obvious, you get to see all of the decks and how they did, and you can decide which of those are relevant, irrelevant, and top. Even then, everyone will still have their own opinion, but it's much more obvious then, than now
But nobody should stop y'all from trying! It's fun anyways, i'm just saying this to let people know, probably best to take this with a grain of salt. Metas change, adapt, and rejuvenate at times. Some decks, like Greninja, stay within a spotlight for a very long time, while others, such as many Trashalance Garb variants, can fall from glory they once had.
It'll be fun to see what you guys come up with, and how it changes over time!