There are a number of racquetball specific entities that operate as charities.
Other groups use racquetball tournaments to support charities.

In the past, I’ve volunteered as a ref at the Georgia Women’s Racquetball HOPE for a Cure tournament.
I don’t expect to be able to make it this year, but I do still support the idea.

An article about the event was posted here:

http://georgiaracquetball.info/2017-hope-for-a-cure-breast-cancer-shootout/