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.
Plot Factory - Online story planner, organizer, and writing application.
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
Scrivener - Scrivener is a content-generation tool for composing and structuring documents.
Slack - A messaging app for teams who see through the Earth!
World Anvil - World Anvil is a worldbuilding tool for Authors, Storytellers and worldbuilding lovers.