I'm a long-time DE user, however there are some circumstances under which I prefer to use different tiling-based WMs instead of GNOME or KDE (I use GNOME mostly for last year or so).
I've got Fedora 22 Workstation installation, with GNOME installed. For most time on both of my machines I run GNOME. However, sometimes I prefer to run XMonad (for me this doesn't matter much actually - i3wm, xmonad, spectrwm - for all of those 3 I've got nice configurations that I can use).
On XMonad (any non-DE e.g.), I'd like to have some scripts & programs to run when the session starts. Is there any standard way to run them without altering /etc/X11/sessions scripts?
For example, having a user-defined session for GDM or something like standard autostart files or anything. I've used to run all this through ~/.Xsession or ~/.xinitrc, but GDM doesn't execute those.