Cloud Productivity Suites

A zero knowledge cloud productivity suite. Provides Rich Text, Presentations, Spreadsheets, Kanban, Paint a code editor and file drive. All notes and user content, are encrypted by default, and can only be accessed with specific URL. The main disadvantage, is a lack of Android, iOS and desktop apps - CryptPad is entirely web-based. You can use their web service, or you can host your own instance. Price for hosted: free for 50mb or $5/ month for premium.

A platform providing online services based on principles of freedom, privacy, federation and decentralization. It is an implementation of NextCloud, with strong encryption configured - it is widely used by journalists, activists and whistle-blowers. It is free to use, but there have been reported reliability issues of the cloud services.

A complete self-hosted productivity platform, with a strong community and growing app store. NextCloud is similar to (but arguably more complete than) Google Drive, Office 365 and Dropbox. Clear UI and stable native apps across all platforms, and also supports file sync. Supports encrypted files, but you need to configure this yourself. Fully open source.

An open source platform for self-hosting web apps. Once you've set it up, you can install items from the Sandstorm App Market with -click, similar to NextCloud in terms of flexibility.

Vikunja is an open-source to-do application. It is suitable for a wide variety of projects, supporting List, Gantt, Table and Kanban views to visualize all tasks in different contexts. For collaboration, it has sharing support via private teams or public links. It can be self-hosted or used as a managed service for a small fee.