Nothing brings out the kids and families like a petting zoo! Unless you have access to your own farm animals, you’ll need to find a local events business that specializes in pet farms for parties.
You can even contact your local zoo to see if they’ll help (showcasing smaller reptiles, etc.). They may be happy to provide you with discounted rates in return for promotion and awareness to the families that attend your fundraiser event. Bring in some local animal experts (like Vets) and make your petting zoo fundraising event educational as well. You can have scheduled hourly talks by animal experts. Charge enough in admission fees to make the event worthwhile and make sure you have insurance coverage.