Where to buy English e-books other than Amazon?

Hi All, i am slowly reducing buying goods and services from USA, especially from Trump‘s circle. That includes Amazon. I haven‘t bought any goods from amazon for a few months already but I still use audible subscription and buy e-books for my kindle. I think I can use storytel for audiobooks in Germany but for ebooks I don’t know which service is good. I have a kindle and an iPad (yes both produced in the USA but they are old and I wont replace them) What do you have as an alternative to amazon ebooks in English language in Germany to be used with kindle or ipad?

Edit:thanks everybody for the suggestions. I will definitely use them in the future. I checked all of them, searched a book that I bought as a kindle ebook yesterday, from 2016 by a British writer. Unfortunately it was nowhere to be found as an ebook. I found a hard copy in the www.worldofbooks.com for uk readers. I can‘t believe amazon ebooks don’t have an alternative for some books. We let amazon be a monopoly, so sad