Here is another amazing photography website in which the photographer allows his images to be used for personal or commercial purposes under a Creative Commons Zero license. These photos are just all around cool - bright, fun, expressive, and sometimes even a little strange. I think it would be great resource for EL, ELA, or vocabulary PowerPoints. Easier to scroll through than Unsplash.
More beautiful photos at Superfamous, which allows personal and commercial use under a Creative Commons Attribution 3.0 license (must provide credit back). Great photos here, many of nature, plants, and lots of "geology" photos. I say geology loosely because I don't really know anything about science. So I could be wrong.
Photography Sellers on TPT
Clip artists are abound on TeachersPayTeachers, but did you know that many sellers are now selling their original photography for commercial use? These are affordable and support real teachers. Most of their products come in related bundles, so it's easy to grab a package of insect photos for a product on insects, for example. Here are some amazing photo sellers I have come across:
Photos 4 Teachers - Strawberry Shortcake - Worth a Thousand Words - Photo Shop