Hey there! Welcome to RU and I have the answers to your questions (hopefully lol):
The best place to start for any tier is the Viability Rankings right here:
https://www.smogon.com/forums/threads/ss-ru-viability-rankings-crown-tundra.3676023/
They tell you what's good and what isn't based on their ranking.
Another thing to check out that goes hand-in-hand with the VR is their SmogDex entries which lists sets favored by each mon and what they do, what teammates work best with the mon, etc. That's here:
https://www.smogon.com/dex/ss/pokemon/
As far as the most interesting play style, in my personal opinion, I'd go with either bulky offense or balance. They both seem to be the best ones right now since Light Clay got banned in UU and hyper offense with screens lost some credibility.
Hope this helps!