FFmpeg Utilities has a Color Syntax section with 140 standard X11 colour names.
What’s lacking is any visual colour rendering, forcing you to search elsewhere.
Wikipedia shows a Color name chart of standardized X11 color names from the X.org source code but there are 145 colours there.
So below are two montages generated directly from ffmpeg’s libavutil/parseutils.c color_table[] RGB values, sorted by Name and HSV respectively.
They were generated by the Bash script ffmpeg-colours.sh.
