Card Connoisseur Toad
From the Super Mario Wiki
The Card Connoisseur Toad is a purple Toad that wears glasses in Paper Mario: Color Splash. He runs the Prisma Museum. He is first encountered near the blue Mini Paint Star in Port Prisma, where he takes Mario's Battle Cards to examine them. After a battle with a Slurp Guy, the Card Connoisseur Toad will give the cards back to Mario and leave.
After receiving a letter from him in the post office, the Card Connoisseur Toad can be found in the Action Command Dojo. He will open up the door to the Prisma Museum, and he will remain in the lobby of the museum for the rest of the game.