Tape It - App for songwriting & audio recording.
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Songcraft.io - A platform for songwriters to write, organize & collaborate.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
RiffShare - Write down a musical riff, send to band members, collaborate
Slack - A messaging app for teams who see through the Earth!