The Majority of 501c3 organizations have them. They are written into the bylaws. They can be nominal or substantial.

We need to transition our BOD from what is referred to as a "Founding Board" into a "Funding Board".

Two links you should read below.

https://starfishimpact.com/2015/03/go-from-a-founding-board-to-a-funding-board/

http://www.blueavocado.org/content/should-board-members-be-required-give