Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
Gen 9 April update (Top 50, no repeat forms besides regional variants)
some stats
Top 3 types
Ghost: 12
Fairy: 11
Grass/Fire: 8
Bottom 3 types
Poison/Ground: 0
Bug/Normal/Steel/Ice: 2
Rock/Electric: 3
Top 3 generations
Gen 5: 13
Gen 7: 10
Gen 6: 8
Bottom 3 generations
Gen 1: 1
Gen 4: 2
Gen 2: 3