AsteroidOS Sync

Synchronize with your AsteroidOS smartwatchGPL-3.0-or-later

floccus bookmark sync

Sync your bookmarks privately across browsers and devicesMPL-2.0

LDAP Sync

Sync your contacts with LDAPApache-2.0

LDAP Sync

Sync your contacts with LDAPApache-2.0

CalDAV Sync Adapter

Synchronize calendar with a CalDAV serverGPL-3.0-or-later

EteSync - Secure Data Sync

Secure, private and end-to-end encrypted calendar, contacts and tasks syncGPL-3.0-only

Casio G-Shock Smart Sync

Add smart functions to your Casio square BT G-Shock (B5600, B5000, B2100)MIT

Snapcast - multi-room audio in perfect sync

Synchronize audio output across devices/playersGPL-3.0-or-later

SyncMemories

Sync photos fastly using USB capabilityMIT

Infomaniak kSync

Automatically sync your contacts and calendarsGPL-3.0-only

Flym DecSync

Sync RSS without a server using DecSyncGPL-3.0-only

spaRSS DecSync

Sync RSS without a server using DecSyncGPL-3.0-only

Kolab Client

Sync contacts/calendarGPL-3.0-only

MoneyBuster

Multi-project shared budget manager able to sync with self hosted FOSS servicesGPL-3.0-or-later

DecSync CC

Sync contacts, calendars and tasks without a server using DecSyncGPL-3.0-only

Joplin

a note taking and to-do app with sync between Linux, macOS, Windows, and mobileMIT

Kolab Notes

Write notes and sync them with KolabLGPL-3.0-only

ImapNotes2

Sync your notes with iOs devices and different accounts like Gmail and othersGPL-3.0-only

LaaNo

Bind notes to links and sync them with NextcloudGPL-3.0-or-later

Tasks.org: Open-source To-Do Lists & Reminders

Private, ad-free task lists! Optional sync with Google Tasks, CalDAV or EteSync!GPL-3.0-only