I'm not sure how much you're trying to donate, but if i were to donate a couple
hundred dollars, I'd probably buy something from Chris Burkard's gallery. If you're not familiar with him, he's LDS and I'm not big into photography, but he seems to be very popular if not the most popular nature photographer. https://www.chrisburkard.com/Shop/AUSTRALIA-FIRE-RELIEF/
100% of print sales go to support the fires, and I'm pretty sure he's done some research on good companies to donate to.