CherryTree, Milanote, Nuclino, Notesnook, Trilium Notes, Notebooks, MacJournal, wikidPad, Nimbus Note, Maxnote, Cryptee, Notally, Zoho Notebook, Omni Notes, Simple Notes, SSuite CleverNote PIM, SilentNotes, Quicknotes, Centrallo, Encryptic, Daymate, Gruik are some alternatives to OpenNote.