Great gameplay, shame about the graphics

[The_Liquid_Laser]

I'm going to ignore games that have "bad graphics" just because they are old.  Here are some really fun games that had umimpressive graphics even when they were brand new.

Katamari Damacy
Tetris
Puyo Puyo Tetris
Minecraft
Castle Crashers
Scott Pilgrim vs the World
Minesweeper
Dragon Quest Builders
Undertale
Untitled Goose Game
Cadence of Hyrule
Dead Cells
Wargroove
Pixeljunk Monsters
Super Mario Bros (looked dated compared to arcade games)
Suikoden (reviewers complained it was 2D.  Heh, it aged so much better than most PS1 games.)

Basically graphics only matter a little.  Pretty graphics are a nice enhancement, but they don't make or break a game.  Gameplay, controls, interface, setting, etc... these things actually matter a lot more than graphics.