Outlook Google Calendar Sync - Offers calendar synchronisation between Outlook and Google, including attendees and reminders.

Google Contacts - Google Contacts is Google's contact management tool that is available in its free email service Gmail, as a standalone service, and as a part of Google's business-oriented suite of web apps Google Apps.

gSyncit - gSyncit Outlook Cloud Synchronizer. Outlook Calendar, Contact, Task, Note Synchronizer supporting Google, Toodledo, Evernote, Informant, iCloud, AOL, Yahoo, Synology, Fruux, Memotoo and CalDav/CardDav services.

SA Contacts Lite - SA Contacts Lite app comes up with features to help you in transferring all your contacts in your phone book between all your handheld devices without much of a stretch.

EteSync - Secure, end-to-end encrypted and journaled personal information synchronization.

Kontact - Kontact is the integrated Personal Information Manager of KDE.