Have been going on game-dev chats and asking about tools for drawing pixels that aren't square, and getting replies of, "What do you mean, pixels are *always* square". 😅
@xinjinmeng Forgive these people; they are ignorant of the old magic.
Aseprite supports double-wide and double-tall pixels. Unsure if you want something like the SNES's 8:7.
CGA and EGA pixels are 1.2 to 1. 😅 Contemporary artists were well aware: DeluxePaint automatically compensates on the circle- and square-drawing tools, for it.
I don't think there's *any* platform that is truly "2:1". C64 is 1.2:1; Atari is slightly more than 1.2:1; PC Engine is slightly more than 1.2:1, etc.
All of those machines from the era of using a TV as the display are gonna have different aspect ratios for NTSC/PAL, too!
Shit, perfect tickling of my c64 nostalgia would arguably involve drawing everything at the almost-1:1 and/or almost-2:1 ratios of a PAL c64, then displaying it at the 0.75:1/1.5:1 ratio of an NTSC C64, since most of my collection was stuff that made the long journey from Europe to a local pirate BBS.
I have made Illustrator do NTSC C64 pixel aspect ratios: https://egypt.urnash.com/blog/2021/05/08/cracked-by-bde/
and if you are willing to be less-than-precise you *could* just do everything in 3d and use a similar filter pipeline to get whatever aspect ratio you desire, or use higher-res aliased sprites scaled down and put through the same pipeline, though it'd be gleefully disregarding the subtler limitations of whatever platform you were scaling to...