Atari ST/STe video monitor RGB DIN13 to VGA adapter adaptor for 15kHz monitors | eBay
ATARI ST / STE RGB to VGA video Adapter with AV RCA and JACK - Share Project - PCBWay
Centurion technologies - If you are looking for a convenient way to connect your Atari ST/F/FM/E to a VGA monitor, while having a possibility to easily switch between Low/Med and High resolutions,