Often you can buy direct from the author or publisher. If your goal is to avoid Amazon (although I admit I don't know how this will affect revenues to the author/publisher), you can get in touch with your local bookstores or places like https://www.indiebound.org/

We are fortunate to still have a Barnes and Noble nearby. Hope it stays open.

Any other source?

The real reason for this is, Powell has it's own book store that competes with Amazon.