Comment by genewitch

i was going to collate a list, but instead https://www.lemkesoft.info/files/manuals_gc12/GraphicConvert...

That supports 200 image file formats as inputs, and you can then export it to PNG or GIF or BMP.

Your question, on its face, seems ok, but really, there's probably millions of image file formats lost to the sands of time. Shareware image creation programs, tiny fly-by-nite company's software that only ever had one major release (probably some cad formats in there. Those were where i used to always have problems 22 years ago when i did this for work.)

however, at least 200 of them are preserved through that "company's" dedication to this topic.