It's Day Eighteen of #RPGaDAY2023 and the question is a tricky one - favourite game SYSTEM. When I answered it back at the beginning of #RPGaDAY I was incredibly cheeky and picked the flipping game system I designed, Vortex, as my favourite system.
I guess you have to like your game system to work with it, and since that video it has evolved into a second edition that's even faster and easier to use. May not be everyone's cup of tea, but I like it, and have another couple of games in mind that I'd love to use it on, if I'm allowed (while I designed it, I don't have complete ownership of it).
Second Edition was influenced by the eye opening simplicity of the Year Zero Engine. I read Tales from the Loop and was just amazed at how small the rules section is in the game, and how much fun the games were that we played in that setting.