Free Web Resources List
I tried to pull out the list of resource sites theluthier featured in the Sourcing Third Party Material in Your Work livestream, as well as add some others I know. I don't know if this is posted somewhere else — I couldn't find it when I looked, but I thought it might be helpful.
Since the forum doesn't like a post full of links, however, I've pulled it out into a Google Doc you can find at https://hdp.rocks/freeresources
I'll try to remember to update the doc as I find new stuff.