Commodore 64 on a VGA CRT monitor - the cheap and cheerful way!
A Dual Monitor Setup For The C64, And Yes, It's VGA Compatible | Hackaday
AV-Monitor Kabel suitable for Commodore C64, 128, +4, 16, 116 and Atari 600XL, 800XL, 65XE und 130XE | Sintech-Shop - Spare parts for mobile phones, game consoles and more
COMMODORE 64 C64 to 1084S / ST Monitor (with 9D socket), Lead / Cable with audio £16.50 - PicClick UK
Portta S-Video to VGA Review | C64 OS
Commodore 64 C16 C128 converter VGA for monitor/TV