ToDoList, CherryTree, TiddlyWiki, Tree Notes, Notesnook, Ecco Pro, TreeLine, CintaNotes, wikidPad, Nimbus Note, OutWiker, OpenJean, Zoho Notebook, Tree Notebook, InfoQube, AllMyNotes Organizer, Natara Bonsai, Fish Code Library .NET, Free DocusTree, BrainStormWFO, gjots2, AML PAGES, Golden Rules Organizer, CUEcards, TexNotes are some alternatives to TreePad.