I have always found people doing charitable work and given them money or supplies. For example, the lady I adopted one of my cays from fosters kittens. She does it on her own. I give her money every year even though she's not registered as a charity because I admire what she does and I know it can get expensive.

When u lived in another state, there was a lady who helped with Guinea pigs that were being abandoned at the ASPCA (who didn't know how to or care to learn to properly care for them) and helped rehome them. She refused money, but gladly accepted bolts of fleece she could use for washable bedding and cuddle cups I made her.

Direct donation is the best way. At least it will be going to who you expect.