I saw Baldur post about this idea so I'm doing the same! Ideally, I'd either expand or version my uses page so that'd be a living version of this.

• Mail Client: On my phone, I use K-9 Mail. On my laptop, I tend to use Fastmail's Web interface.
• Mail Server: Fastmail!
• Notes: Obsidian mainly on my laptop and Nextcloud Notes on my phone.
• To-Do: Nextcloud Tasks that integrates with Fastmail and Tasks on my phone.
• Calendar: Nextcloud Calendar!
• Cloud Storage: A self-hosted instance of Nextcloud
• RSS: On desktop, GNOME Feeds; on mobile, Feeder.
• Contacts: All synced to Nextcloud Contacts; on my phone, I use davx5 to pull it down.
• Browser: Firefox on desktop and mobile, though I'm using GNOME Web more.
• Chat: Whatever; Slack, Matrix, IRC, XMPP. I'll actually update my contact page to make this more clear.
• Bookmarks: Firefox's native bookmarking and my own site
• Read it Later: A self-hosted tool that syncs to my eReader.
• Word Processing: LibreOffice Writer. It really does the job for my short stories and longer form writing.
• Spreadsheets: LibreOffice Calc. Does what I need for my personal life and the dozens of flat-file databases represented by it I interact with.
• News: Through my RSS feeds!
• Password Management: Vaultwarden
• Code Editing: Neovim
• Books: On the Web, I use Goodreads (ick) and Bookwyrm. On my desktop, Calibre is how I manage my library. All of that syncs with my digital collection on my eReader. Offline, I keep a notebook with notes and constantly shift around my stacks of books.
• Blogging: All hand rolled using IndieWeb standards. I wrote this using Quill, maintained by Aaron!