Trademarks
Here you'll find a list of the things that have come to be associated strongly with Chris over the years. They are his trademarks.
Survival Knife
The survival knife has been associated with Chris since the very first moment we saw him. His original costume prominently displayed his knife on his left shoulder, facing downwards for ease of access. He also begins the first game only with the knife, unlike Jill who begins with a gun. He also begins Code Veronica in much the same way.
The survival knife is perhaps a vital sign of Chris' personality. He doesn't require a gun to take things down (although that is his speciality), he's just as willing to get down and dirty and use his knife to get the job done. He's rough, perhaps a little crazy, but never defenseless. When Chris is on the job, his knife is never far from sight.
Green
The colour green has also been associated with Chris since day one. His original uniform was green in colour, as was his Code Veronica outing. Up until this point, every costume we've seen Chris in has been green. Even when he's not in uniform his clothes have usually been green.
Green is considered to be the most restful colour. It symbolises self respect, well being and balance. It also represents harmony, learning and growth, and the life force of people. Some people also think you should wear green when you want to overcome a sense of thwarted ambition. Perhaps this colour represents Chris' inner being, that of a balanced soul after growth and harmony in the world. It certainly suits him.
Guns
Obviously being a marksman, guns are Chris' speciality. But there are two guns in particular that are most familiar with Chris; the magnum and the shotgun. Unlike Jill, who gets larger weapons as she progresses through her games, Chris is usually left to fend with only the shotgun. It's very rare he can find anything more powerful. But it's still supremely effective in dealing with enemies, especially for that infamous headshot.
The magnum is also strongly related to Chris. As with Jill, Chris can come across this ultimate weapon in the first game to help finish off the Tyrant, and he can also obtain it during Code Veronica as well. In fact, during the Code Veronica battle game it's one of Chris' standard weapons, along with his shotgun. Whenever Chris is around weapons, it's usually always with these two and his knife.
Made In Heaven
"Made In Heaven" is a phrase that's been associated with Chris since the beginning as well. It was originally his alternate costume in the first game, a brown bomber jacket with the slogan printed across the back. This is based on actual military jackets that bear the same image and slogan. A nice choice, as Chris used to be in the military, and the phrase really does seem quite fitting. Chris wears this same logo in Resident Evil 2 and the more recent Remake as well.
"Made In Heaven" is also the name of a Queen album. At first glance this may appear to be nothing more than coincidence, but other characters throughout the series have also born Queen songs on their outfits in some way. Claire has worn a vest with "Let Me Live", while Billy sports a "Mother Love" tattoo on his arm. You can find out more about this particular album here.
Airplanes
As a former pilot, it's no surprise that various flying crafts have come to be associated with Chris Redfield over the years. Although he wasn't the pilot for the S.T.A.R.S. alpha team, he's still more than competent and accompanied Brad up front as they flew into missions.
Code Veronica is the first time we actually get to see Chris flying around, as he pilots himself both to Antartica and away from it with his Harriet Jet. This of course has led to many dirty jokes about the size of his jet over the years, but that's a story for another day.