When i first found 12 factor i was really impressed, it was/is a collection of guidelines that suit their defined purpose really well, easy to read and implement.

I always feel like there should be more parts of software/web dev with guidelines like this. An easily digestible format that is easy to discuss with colleagues

other examples i can think. - https://refactoring.guru/ - not exactly a list of guidelines but a nice digestible collection of common patterns, pro's cons and when to/not use them - to a lesser degree, agile manifesto. a nice list of guidelines, but not as implementable (mainly because it is more related to people/management)

but saying that i am not sure exactly what parts of the field i need this for. I didn't know i needed this for building/deploying web apps before i saw 12 factor.

maybe application folder structures, guidelines to mitigate/remove software rot?