Some story with the original RED mercenaries adding their bit of insanity to the somewhat sane galaxy of Mass Effect. How will 9 homicidal maniacs stop a legion of genocidal robot ships? Good question; I have no idea.

The 'Meet the Team' videos with Mass Effect characters. It's not really a crossover because no Team Fortress 2 characters appear, but the format owes everything to TF2. All canon liberties taken in the name of humor.

At the verge of Death and a freak accident with a teleporter, Red Scout is transport into the Mass Effect universe, right in the middle of Shepard's first encounter with the Husks on Eden Prime. A bit dark and grim, with some more realism. No pairing decided

In 1965, nine mercenaries are frozen so that they can save the future. 220 years later, one very specific person thaws them out. Now, these lunatics may be all that stands between Humanity, and the greatest threat of our brief existence.