Linktree - Connect your audience to all of your content with just one link.
Freeplane - Freeplane is a powerful and free software for building mind maps.
Carrd - Simple, responsive one-page site creator.
SuperNotecard - Introducing SuperNotecard. SuperNotecard is an online writing tool that features virtual notecards to help arrange facts or scenes, track details, organize paragraphs, and clarify your composition process.
ContactInBio - Offer More Contact Options To Your Followers
Linked Ideas - A macOS/iOS apps to treat ideas as links of concepts.