Vaporeon

Thanks to its high all-around bulk and access to utility moves such as Wish, Toxic, and Heal Bell, Vaporeon is a premier defensive Water-type in the tier, checking prominent physical attackers such as Incineroar, Passimian, Sneasel, and Rhydon as well as special attackers such as Guzzlord, Houndoom, and Assault Vest Slowking. The combination of Wish + Protect lets Vaporeon both serve as an amazing support Pokemon, keeping Pokemon that don't have access to reliable recovery like Incineroar, Whimsicott, Dhelmise, and Silvally-Steel healthy, and maintain its own health. Because of its ability Water Absorb, Vaporeon is capable of handling opposing bulky Water-types like Blastoise and Slowking while also checking offensive Water-types like Samurott and Omastar. Unfortunately, although Vaporeon has a high HP stat, its physical bulk is lacking, making it easy for Pokemon like Medicham and Dhelmise to pressure it. Additionally, Vaporeon's passivity and reliance on Toxic for damage invite in threatening setup Pokemon like Substitute + Bulk Up Braviary, Taunt + Calm Mind Comfey, and Bulk Up Scrafty that can circumvent Toxic in some way. While Vaporeon's special bulk is great, it can still struggle with common specially offensive Grass- and Electric-type Pokemon like Whimsicott, Sceptile, Heliolisk, and Rotom.