X-mas card by Dave Taylor.

From Marvel Team-Up #1 (1972).
Pencils by Ross Andru

Spider-Man X-mas ad from 1983.

DCU Holiday Special 2009
Cover by Dustin Nguyen

DCU Holiday Special 2008
Cover by Frank Quitely

DCU Infinite Holiday Special 2006
Cover by Howard Porter

DC Comics Presents #67 (1978)
Cover by Jose Luis Garcia-Lopez

Marvel Holiday Special 2006
Cover by Frazer Irving

Marvel Holiday Special 1993
Cover by the great Arthur Adams

Marvel Holiday Special 1991
Cover by the great Arthur Adams

Cover to Secret Wars #12 (1985) alongside Marvel UK’s reprint series.
Here’s a great blog entry on the UK Secret Wars series.

Punisher MAX X-mas Special 2008
Cover by Chris Bachalo

Uncanny X-men #143 (March 1981)
Cover by John Byrne