I have an old 16:10 monitor that I use most of the time since I like the extra height over 16:9.
for gaming or anything art related, I use a 27" ASUS pro-art. I'd use it as my main monitor but it's too big for my desk so I pretty much use it as a TV except when doing anything art related (it has really accurate colors for anything that needs to be printed)
I wish that there were higher resolution 5:4 monitors available, it seems like they all max out at 1280x1024. iirc Huawei made a 4k 3:2 monitor, but it's Huawei so idk how easily it'd be able to get in America.