We do have some customers who use Shelterluv to track donors by entering their donations into the system and also using a "Donor" attribute to categorize them within people records. You could even set up different donor attributes if you need to further categorize them by donor level.

From there, you can run reports for:

• Donations taken
• Donor information (to export to MailChimp or another email campaign service, or for creating mailing labels)

If you need more functionality, we've heard good things from shelters and rescues about Little Green Light, Bloomerang, and Network for Good.