"None May Say What Loki Can Do!" - Loki Art by Jack Kirby

 Loki in All His Glorious Epicness

Vintage Jack Kirby THOR art via Kirby4Heroes

Guardians of the Galaxy by Leinil Francis Yu

Variant cover art for Guardians of the Galaxy issue #3 - plus process line art by Leinil Francis Yu

Iron Man & War Machine Line Art - An Iron Man-ia! Gallery

2 by Bob Layton

Sam Liu

Gabriel Gecko

Tom Hodges

 Francis Manapul

 Chris Samnee

Paolo Rivera

Thor's Day - Pencil & Ink Line Art by Walt Simonson

via The Official Walter Simonson Page