Simplenote

For people who want text and nothing else. Simplenote runs on iOS, Android, Mac, Windows, Linux and the web, and its apps, sync, backups and sharing are all free, with tags for finding things and an optional Markdown preview. There are no notebooks to design and no blocks to drag around, which is the whole appeal and also the limit: if your notes are mostly screenshots and PDFs, this is the wrong tool. Because everything is plain text, leaving costs almost nothing, which makes it a sensible place to wait out your next app crush.