See Radical Red, there's beautiful, detailed sprites for every Pokemon up to gen 8, all within the fire red engine. It won't be long until the same is done for gen 9 after scarlet and violets release.

Pokemon Fan Designs Gen 1 Sprites of Teddiursa, Ursaring, and Ursaluna As for Ursaluna, the Peat Pokemon assumed an aggressive stance, with its left front paw raised to claw its foes and its teeth ...

This Pokemon GO NPC Challenger isn't too bad, though. A Flying-type, a Ground-type, and a Steel-type will work wonders here. 6) Slick Challenger.