OS X X11 applications that could be accessed from linux
Basically every X11 application installed on the target Mac can be run that way, but the default X11/XQuartz installation only includes a few of them.

pse@Mithos:~$ ls /opt/X11/bin
X@               fc-pattern*      makedepend*      xbacklight*      xfsinfo*         xmessage*
Xephyr*          fc-query*        mkfontdir*       xcalc*           xgamma*          xmh*
Xfake*           fc-scan*         mkfontscale*     xclipboard*      xgc*             xmodmap*
Xnest*           fc-validate*     oclock*          xclock*          xhost*           xmore*
Xorg*            font_cache*      quartz-wm*       xcmsdb*          xinit*           xpr*
Xquartz*         fonttosfnt*      resize*          xcompmgr*        xinput*          xprop*
Xvfb*            freetype-config* sessreg*         xconsole*        xkbbell*         xrandr*
appres*          fslsfonts*       setxkbmap*       xcursorgen*      xkbcomp*         xrdb*
atobm*           fstobdf*         showfont*        xcutsel*         xkbevd*          xrefresh*
bdftopcf*        gccmakedep*      showrgb*         xditview*        xkbprint*        xscope*
bdftruncate*     glxgears*        smproxy*         xdm*             xkbvleds*        xset*
bitmap*          glxinfo*         startx*          xdmshell*        xkbwatch*        xsetmode*
bmtoa*           gtf*             sxpm*            xdpr*            xkeystone*       xsetpointer*
cairo-sphinx*    iceauth*         test_xauth*      xdpyinfo*        xkill*           xsetroot*
cvt*             ico*             twm*             xedit*           xload*           xsm*
cxpm*            koi8rxterm*      ucs2any*         xev*             xlogo*           xstdcmap*
editres*         libpng-config@   uxterm*          xeyes*           xlsatoms*        xterm*
fc-cache*        libpng15-config* viewres*         xfd*             xlsclients*      xvinfo*
fc-cat*          listres*         x11perf*         xfindproxy*      xlsfonts*        xwd*
fc-list*         lndir*           x11perfcomp*     xfontsel*        xmag*            xwininfo*
fc-match*        luit*            xauth*           xfs*             xman*            xwud*


If you want more, you install additional packages either by compiling them yourself or by using a package manager like Homebrew.