Self-Hosted Files & Cloud

★ Nextcloud — the heavyweight; sync clients for everything; calendars, contacts, talk, office suite, photos. Default for "Dropbox + Google Drive + Outlook in one."
- https://github.com/nextcloud/server
★ Seafile — files-only focus; faster sync; lighter than Nextcloud. Default for "I just want files."
- https://github.com/haiwen/seafile
OwnCloud Infinite Scale (oCIS) — Nextcloud's predecessor's modern rewrite.
- https://github.com/owncloud/ocis
Pydio — older alternative.

Lightweight file browser (no sync)

★ FileBrowser — single-binary web file manager; the default for "give me a directory listing with a UI."
- https://github.com/filebrowser/filebrowser
Filestash — multi-backend file browser (S3, FTP, SFTP, etc.).
- https://github.com/mickael-kerjean/filestash
h5ai — pretty directory listings for static files.

★ Pingvin Share — Mozilla Send-flavored; encrypted file sharing with expiry.
- https://github.com/stonith404/pingvin-share
Send (Timvisee fork of Mozilla Send) — original spec, still works.
- https://github.com/timvisee/send
OnionShare — share files over Tor; for high-privacy use cases.
- https://github.com/onionshare/onionshare
YetAnotherUploader / PicoShare — minimal alternatives.

★ Syncthing — peer-to-peer encrypted file sync; cross-platform clients.
- https://github.com/syncthing/syncthing
Resilio Sync (formerly BTSync) — proprietary; faster than Syncthing in some workloads.
rclone — see File Sync; for cloud-to-cloud.

★ Baikal — minimal DAV server; tiny resource use. The default for "just calendars and contacts."
- https://sabre.io/baikal/
Radicale — Python; minimal.
- https://github.com/Kozea/Radicale
DAVx5 — Android client (not server) but worth knowing.
- https://github.com/bitfireAT/davx5-ose
Nextcloud / Seafile also include CalDAV / CardDAV.

★ OnlyOffice Document Server — runs alongside Nextcloud / Seafile for Word / Excel / PowerPoint editing in browser.
- https://github.com/ONLYOFFICE/DocumentServer
Collabora Online — alternative; LibreOffice-flavored.
- https://github.com/CollaboraOnline/online
CryptPad — encrypted real-time collaboration.
- https://github.com/cryptpad/cryptpad

For backing up SaaS clouds (Google Drive, Dropbox, OneDrive) into your self-host, rclone is the universal tool.

★ Pick one of Nextcloud or Seafile. Don't run both. Nextcloud for everything; Seafile for files-first speed.
Always run external Postgres / Redis for Nextcloud at any meaningful size; the SQLite default is for trivial use.
Object storage backend — Nextcloud / Seafile both support S3 / R2 backing. Cheap.
Backups — DB + the data dir. Restic to R2 nightly.
Tailscale in front for personal use; Cloudflare Access in front for shared use.