Mira is the perfect place to store all the information about your contacts. It is a free and open source tag training application.
Here are some screenshots to illustrate the features and user interface of this application:
Tagging task algorithm. Screenshot of Mira - 1920px · 1482pxManage multiple instant messaging accounts. Screenshot of Mira - 1920px · 1482pxCustomize your Apple remote to perform other tasks. Screenshot of Mira - 1920px · 1482pxPersonal address book storing contacts, birthdays, emails, numbers. Screenshot of Mira - 1920px · 1482px
Anki
EverNote
QOwnNotes
Rainlendar Lite
CherryTree for Windows