Tangrowth

Tangrowth is an effective pivot thanks to its great defensive typing in Grass, which allows it to check a number of threats such as Ash-Greninja, Mega Diancie, Garchomp, and Tapu Koko. It can perform as a great wall both physically with its Rocky Helmet set as well as specially with an Assault Vest, which is required for surviving hits from Pokemon like Ash-Greninja. Tangrowth is able to fill these roles well due to Regenerator, allowing it to heal off passive damage while switching, retaining momentum for its teammates while still being able to repeatedly switch into the threats that it needs to check. Despite its general lack of power, Tangrowth has great utility moves such as Knock Off and coverage moves such as Earthquake for Heatran, Hidden Power Ice for Landorus-T and Garchomp, Hidden Power Fire for Ferrothorn and Mega Scizor, and Sludge Bomb for Tapu Bulu. However, Tangrowth is relatively passive and relies on its super effective coverage to be a threat, and the Assault Vest set is prone to Knock Off, which means that it has a much harder time switching into the threats that it needs to check if it loses its Assault Vest, especially as the likes of Serperior and Mega Alakazam tend to use Knock Off themselves.