Over the years of Pokémon Showdown has shifted, from Copycat Roar Riolu to Swords Dance Mimikyu. If you looking for the best Pokémon for the current metagame, read below:
Stallers:
Blissey And Chansey are not quite viable anymore. Use Clefairy as another option (it is not in OU but can be used in AG and low tiers). If you are in a pinch, use Clefable or any other bulky Pokémon able to use a healing move and Toxic.
Set-Up Sweepers:
Now these are very common. There is a difference between a set-up and a set-up sweeper. Set-ups are usually Spikes, Stealth Rock, etc. Set-Up Sweepers, on the other hand, are Pokémon with moves like Shell Smash (with White Herb), Calm Mind, Swords Dance, Dragon Dance, and much more. A good Pokémon now is Lugia (seems surprising huh?) with Curse and Calm Mind. Use CM or C depending on whether the opposing Pokémon is more of a physical or specially inclined Pokémon.
Finally, Set-Up:
This is the most common first lead for a party of six. The setup meta used to be Foretress and Skarmory, but now Ferrothorn And Clefable are more viable. Both can use Stealth Rock, and Ferrothorn has Spikes and Leech Seed on it’s side. Clefable can use Thunder Wave.
Stallers:
Blissey And Chansey are not quite viable anymore. Use Clefairy as another option (it is not in OU but can be used in AG and low tiers). If you are in a pinch, use Clefable or any other bulky Pokémon able to use a healing move and Toxic.
Set-Up Sweepers:
Now these are very common. There is a difference between a set-up and a set-up sweeper. Set-ups are usually Spikes, Stealth Rock, etc. Set-Up Sweepers, on the other hand, are Pokémon with moves like Shell Smash (with White Herb), Calm Mind, Swords Dance, Dragon Dance, and much more. A good Pokémon now is Lugia (seems surprising huh?) with Curse and Calm Mind. Use CM or C depending on whether the opposing Pokémon is more of a physical or specially inclined Pokémon.
Finally, Set-Up:
This is the most common first lead for a party of six. The setup meta used to be Foretress and Skarmory, but now Ferrothorn And Clefable are more viable. Both can use Stealth Rock, and Ferrothorn has Spikes and Leech Seed on it’s side. Clefable can use Thunder Wave.