Age of Arthur is a set of free wargames rules for Romano-British skirmish games. This is a period that has long attracted my attention.
Saxons and Vikings is a set of four page simple rules for Dark Ages battles
Here’s a short photo tutorial on making a dark ages livestock corral, which is perfect for your SAGA games.
Kings of War is a great free fantasy rules set from Mantic Games. Here’s a variant for the Viking Age
Ravenfeast is a set of free wargames rules for skirmishes in the Norse sagas.