Free open source alternative to Google Keep. It lets you take notes and sync them with a NextCloud account. The apps are available for Android (through F-Droid and Google Play) and NextCloud.

Fediverse address:
@Carnet@framapiaf.org

Free open source note taking and to-do app which you can sync online with lots of popular cloud services including Nextcloud. Available for Android, iOS, Linux, Mac and Windows.

Fediverse address:
@joplinapp@mastodon.social