Supernote seems to be a popular alternative.
I'm kind of hoping Amazon create one, and use ebook sales to subsidise the hardware cost.
Amazon doesn't really seem to subsidize ereader hardware except maybe in countries where they are "losing" like Canada. Like compare what you get with a Boox Leaf or Boyue P78 for the price of a Kindle Oasis.
Usually a comparable Kobo or Pocketbook is within spitting distance if not cheaper. The 6.8" Paperwhite somewhat upset the balance as they don't have a direct response to it right now. A Kobo Libra 2 is 90% of what an Oasis is for 2/3rds the cost. And no ads.