Microsoft OneNote, GoodNotes, Adobe Acrobat Reader, Concepts, CollaNote, Drawboard PDF, Microsoft Whiteboard, Excalidraw, Penly, OpenBoard Whiteboard, Stylus Labs Write, Bamboo Paper, Evince, MuPDF, Skim, Notesnook, PDF Expert, Butterfly, NightPDF, Heynote, Scrivano for Handwritten Notes, MrWriter, Journalify, GitJournal, Saber: Handwritten Notes, NoteLab, AppSoftware Journals are some alternatives to Xournal++.