The old Commodore Amiga monitors, such as the 1080 and 1084, are still available used in the U.S..
These work quite well on A1000 and A500 computers with no adapters - just plug them in.
I still use a A1000 with a 1080 Amiga monitor that has great color display. It is on the small side at about 15".
I just picked a 1080 up at a flea market for $15.00. These can also work great for older Commodore C-128 systems.