Obsidian, Standard Notes, Joplin, Simplenote, Evernote, Todoist, Typora, Workflowy, Notezilla, Notebook PEA, Quillpad, Pystickynote, Remember The Milk, Turtl, Goblin Tools, NoteLedge, Zoho Notebook, Beaver Notes, Silverbullet, Simple Notes, Synapbook are some alternatives to Google Keep.