Kontact
Open Source
Kontact is a personal information manager and groupware software suite developed by KDE. It supports calendars, contacts, notes, to-do lists, news, and email.
fruux
Freemium
fruux is a cross-platform synchronization service.
Memotoo
Commercial
Memotoo sync all your contacts from Gmail, Facebook, phone, Thunderbird, Outlook, etc in a single address book.
FCorp ID Book
Free
FCorp ID Book is a portable, light but powerful address book.
Compare FullContact with alternatives
Compare Kontact and FullContact and decide which is most suitable for you.
Compare Memotoo and FullContact and decide which is most suitable for you.
Compare FCorp ID Book and FullContact and decide which is most suitable for you.