Conversation so far:
what is a charity john mayer works for?
Mayer created the "Back to You" Fund.
what does this charity do?
focuses on fundraising in the areas of health care, education, the arts and talent development.
how does the charity raise money?
The foundation auctions exclusive John Mayer items.
did the charity earn a lot of money?
The auctions have been successful, with some tickets selling for more than seventeen times their face value.
what is a type of philanthropy he works with?
Mayer participated with Zac Brown in a benefit concert in Bozeman, Montana where they raised more than $100,000 for firefighters.

Question: does he work with any other artists for charity?
Self-contained rewrite: Besides Zac Brown,does John Mayer work with any other artists for charity?