Hampton from Hybrid Calisthenics (find him on YouTube) has some of the best content I’ve found, personally, for calisthenics, both informational and his routine is free and made a huge difference for me!
I can second this program. I am usually into kettlebells, but for several months I was travelling and required an alternative. This program is an open version of the "Convict Conditioning" program which works just as well. I've been using several months and now that I have returned to KB and clubbells I have retained the pushup and pull-up progressions.
I love how each exercise has a difficulty "slider" so you can choose the one variation that fits your current fitness level. Really good shit!