I don't know how important or essential they are, but these apps are missing in Fedora: beforelight constype fslsfonts fstobdf grandr ico lbxproxy mkcfm mkcomposecache proxymngr rstart scripts showfont smproxy transset xcmsdb xdbedizzy xditview xdriinfo xf86dga xfindproxy xfsinfo xgc xman xmh xmore xphelloworld xplsprinters xprehashprinterlist xrx xtrap $HOME=http://xorg.freedesktop.org/archive/individual/app/
Thanks for taking the time to make this list, however I doubt there is value in adding these apps simply because they exist. Now if there is a specific use-case for one or two, I could add those to xorg-x11-apps, but adding them all just because they exist seems counter productive.
xrandr sets resolution modes.Have a game crash on you and you will see the need for it to reset your screen resolution. xdriinfo is used similarly to driconf, it helps with diagnosing issues.