I am going to form a competitive team, but I need to know what are the viable or reccomended Pokémon for the tier. Include some sets, counters and checks please.
Here is a link that a helpful person gave me on Showdown. This will show you all the 'top' Uber Pokemon
It appears that you were correct sumwun, Primal Groudon is the most used Ubers at this point in time