Your best options are going to be from Japan because they have the biggest dumbphone market in the world, so companies still design new ones. Your best option will be through smaller 3rd party sellers or directly from the manufacturer’s site. Many Youtube videos in the dumbphone community can give you better examples. Just be careful about getting a phone that is 4G or 5G because 3G service and under is getting cut everywhere. Also, asian networks use different frequencies than us in the Americas