In no order:
An American Tail: Fievel Goes West
Fistful of Dollars
For A Few Dollars More
The Good, The Bad, and the Ugly
The Good, The Bad, and The Weird
Once Upon a Time in the West
Once Upon A Time in Mexico
Once Upon a Time in the Revolution/Duck, You Sucker
My Name Is Nobody
A Genius, Two Partners, and a Dupe
The Man Who Shot Liberty Valance
The Apple Dumpling Gang Rides Again
Support Your Local Sheriff
Support Your Local Gunfighter
Two Mules for Sister Sara
The Sons of Katie Elder
The Magnificent Seven
Back to the Future III
Desperado
The Big Gundown
Companeros
The Mercenary
The Searchers
The Shootist
The Paleface/The Shakiest Gun in the West
Son of Paleface
The Sacketts
City Slickers
Blazing Saddles
Navajo Joe
Open Range
Maverick
Dead Man
McClintock
High Noon
Shane
True Grit
El Dorado
El Topo
Sunset
Ace High
You could say I love the genre...