I think you missed heat haze/stealth field from ninth :
www.panda3d.org/forums/viewtopic.php?f=8&t=15285
I have a simple ‘posterize-pixelize’ shader that I used for pyweek if you want another effect:
pyweek.org/e/wez/
There where also some interesting effects in Demomaster (like turning the scene into ascii-art).
And maybe it’s beyond the scope of common filters but maybe deferred lighting could fit somewhere in there?