Home equipment for human flag progression

My goal for 2026 is to progress up to doing human flags. My preference is to do this at home, and I am wondering what sort of equipment I should purchase or, ideally, build, to begin progressing.

I understand that each progress routine is different, but I am curious if there are any must-haves. Pull-up bars seem like an obvious go-to, but I want to know about anything else that folks have found useful. Ideally, pieces would allow for multiple exercises, but it is not by any means a requirement, so long as it's useful.