I'm looking for the complete Silent Hill comics collection, is this it:
Silent Hill Omnibus (Dying Inside, Among the Damned, Paint it Black, The Grinning Man, Dead/Alive)
Silent Hill Sinner's Reward
Silent Hill Past Life
In print form that's everything. The Silent Hill Experience UMD which was released a few years ago also contained an UMD-exclusive comic titled The Hunger.
There are also like...three short comics by Hiroyuki Owaku and Masahiro Ito. I think two of those three were only released for Japanese cell phones though..the third was included with the Origins Soundtrack.
I stress "short" though. Really only worth your time if you're really curious..there's just not a lot too them.