NextCloud (and its many applications) is my primary use case for self-hosting.

NextCloud is a self-hosted personal Cloud that puts you in control of your documents/files/data. It can be used from anywhere via desktop, web or mobile app it incorporates military-grade end-to-end encryption for security and privacy. NextCloud provides:

• Cloud Storage/Secure File Sharing - replaces Dropbox/Google Drive/iCloud, etc.
• Office Apps - replaces Google Docs/Sheets/Office 365, etc.
• Notes - replaces Evernote/OneNote/Apple Notes, etc.
• Contacts/Calendar/Tasks - replaces Outlook/iOS apps
• Email Client - replaces Gmail/Yahoo/Hotmail/Outlook
• Photo Gallery - replaces Google Photos, etc.
• Password Management
• Bookmark Management (which automatically saves archived versions of bookmarked pages in case they're depublished!)
• and much, much more - including integrations with many other apps including Draw.io, Pico CMS, Dokuwiki, and numerous others.