Many organizations offer financial support for German as well as foreign students at German universities. You can search the DAAD Funding Guide for offers that might be interesting for you. Other online databases are the so called “Stiftungsindex” and the database provided by the “Stifterverband für die deutsche Wissenschaft”.
For students and researchers from Estonia, Latvia and Lithuania, the DAAD offers a wide range of scholarship opportunities. Specific offers for this region from other organizations you will find here.