Hi,
I am missing quite a few because the new search here does not work very well, but some threads relevant to AM5.x:
division: Another bunch of rules variants
parma: Variant Rule: Improved Parma
gurps am: Ars Magica needs a fatiguing mechanic for magi
some essentials: Game: Simple but Huge (House Rules)
But... for AM6, I'm less interested in the kind of rules variants I've posted here because I think the more important changes are more fundamental, especially after seeing Erik's character advancement threads, eg Ranulf from MoH now 150 years post apprentice!!!!
Anyway,
Ken