urxvt bold colors are wrong - bold #0-7 are using colors from #8-15

Use the +is commandline flag, or (exactly equivalently), set the intensityStyles resource to false. From the man page:

intensityStyles: boolean

When font styles are not enabled, or this option is enabled (True, option -is, the default), bold/blink font styles imply high intensity foreground/background colours. Disabling this option (False, option +is) disables this behaviour, the high intensity colours are not reachable.

So, in .Xresources:

URxvt.intensityStyles: false

It's not clear which behavior is "right". (I prefer "bold" = "bold font".) Historically, some terminals treat SGR 1 ( \e[1m ) as "bold", and others treat it as "intense". Current terminals exhibit a mix of behaviors. Top row in each window is colors 0 through 15 in "bold". Second row is without "bold". (-bdc and +bdc is the XTerm equivalent of URxvt's -is and +is -- not sure why it only appears to affect color 0 on my system)

script to run the terminals in this image