This section deals with "fan-made", but this is probably better describes as Non-Lucasfilm licensed helmets and armor. I say this since this can wary between a single guy manufacturing out of his garage to a complete business turning out hundreds of helmets and props per year. Basically this is the stuff produced without Lucasfilms consent.
However the results are often stunning!

Stormtroopers	Darth Vader	TIE Pilots
AT-AT Driver's	Biker Scouts	Other Imperial's
AotC & Exp Universe Clone Trooper	RotS Clone Troopers	Rebel Alliance
Droids.	Jango Fett	Boba Fett
Chewbacca, Yoda and the  Good Guys.	Tusken Raider's, Jawa's and the Scum of the Universe