There is a feeling that is easy to have when you go to write a game, that you’re going to write the whole game from scratch, 100% novel; and this is a neat thing to try, “outsider art” is capable of escaping the extant perceptions that limit artists working in a genre. It’s also the hardest path, because you can’t learn from existing theory and practice, you have to create the metaphorical universe where an artist inside the space can just buy a bag of flour, a tub of butter, and some apples. If you still want to take the hard road, be my guest, I’m sure you’ll make something cool, but if you want a rest, here are some things to help you build
SRDs
A System Reference Document is an explicit attempt to offer the theory behind game design for others to use. A very useful element of an SRD is that it’s existence explicitly grants permission to use the design work
Here Kyle Tam has compiled 9 SRDs for Dicebreaker, including Lumen, a lightweight fast paced videogamey action system; and Caltrop Core, a hyper lightweight d4 general purpose system. https://www.dicebreaker.com/categories/roleplaying-game/best-games/best-rpg-systems-hack-custom-game-srd
Using an SRD does not mean creating a “clone” of some other game, instead they give you access to a set of tools that will solve many problems, so you don’t have to solve all of the problems yourself; and usually there is a community around the SRD which has tested, refined, and experimented with altering those tools, giving advice and examples for how to use and bend the SRD, again without doing all of the work.
It’s important to remember that we live in a society, and that means we help each other, actively and by existing in other people’s past for them to learn from, stand on, climb above.
Icons
In Sepjember it’s important to keep goals in mind. You could absolutely make a PbtA or FitD game, but those are big systems that ask you to produce quite a lot of stuff to make them work. It is impractical, but not impossible, to make such a large game given our constraints. Also, there is no literal PbtA SRD, instead you look at Apocalypse World and use it as if it were one; or you might use something newer that has already evolved on the ideas in Apocalypse World. This gets a little tricky. Apocalypse World declares itself willing to be derived from, not all games do.
Here are some:
… I’ll get some more