WSCAOS is a d6-based game about being cool space adventurers having cool space adventures! The rules are simple and lean into action and keeping things happening. It's great for oneshots but could certainly be used for longer games.
(It's also the base for a large group of games in a similar style spanning various genres; there was a 'what's so cool about' game jam on itch.io, but this is the first one.)