[palehose]

I'm not affiliated with Taproot, but am aware of them and that they have been successful with their model.

Taproot Foundation - WHAT WE DO: The Taproot Foundation connects nonprofits and social change organizations with passionate, skilled volunteers who share their expertise pro bono. Through our programs, business professionals deliver marketing, strategy, HR, and IT solutions that organizations need to achieve their missions. https://taprootfoundation.org/