I was a guitarist before I got into synths (unless you count the SK-1 I grew up with) so I've got quite a few pedals lying around. I run a lot of things through Strymon Mobius - Boss DD-500 - Neunaber Immerse Mki. My favorite to do this with is probably the MEGAfm since it has no onboard effects and really benefits from them.
I also crank my Neutron through a WMD Geiger Counter.