Karts, track pieces, furniture, golf balls and props: Kenney (kenney.nl), CC0. Racing Kit, Car Kit, Toy Car Kit, Graveyard Kit, Furniture Kit, Minigolf Kit, Weapon Pack.
Sound effects: Sonniss GDC bundles (3maze, Shapeforms, Sounds Great, fascinatedsound, Sound Spark LLC, Cinematic Sound Design, Chris Logsdon, Epic Stock Media).
Music: Abstraction (Tallbeard Studios), "Three Red Hearts Box Jump" and "Have A Great Summer".
Physics: Rapier (Dimforge). Rendering: three.js by mrdoob and contributors. Fonts: Kenney Future, Space Grotesk.