https://wodblock.com an app to track workouts, can generate functional/hiit workouts too using AI (give me something leg heavy but with some cardio, etc).

https://jazzcatalog.com an app the learn jazz standards. You upload PDFs and it extracts the songs, can add annotations, metronome, some have associated youtube video. Working on adding tools to record loops through audio interface, AUv3 effects, MIDI.

https://music.nicotejera.com a variety of tools I built for myself to learn music theory, ear training, etc.