In the film, we see two extremes - he either has basically no weapons other than his swords and one gun (in-universe, because he forgets the bags, out of universe because the studio was too cheap for a shootout scene). Or, he has a bagful of guns, on top of his two swords.
Comic Deadpool is generally depicted as having two swords (sometimes just the one, but usually two) and a varying number of firearms. The most common seem to be:
- Pistols (Like the swords, either one or two. This way, he can choose to wield two swords, two pistols, or one of each)
- Submachine Gun (Like a Skorpion)
He also has access to other weapons, but these are very situational or specific to certain fights, so aren't very common. Stuff like Assault Rifles, Shotguns, Rocket Launchers etc. He's extremely proficient with weapons of all kinds, including hand-to-hand (He was a badass Mercenary/Bounty Hunter before he even got powers).
Personally, whenever I picture Deadpool he's got two katanas strapped to his back and two semi-automatic pistols holstered at his hips.
Ok referring to Marvel's Contest of Champions game here, Deadpool has three special attacks
- Spinning groin punch
- Spinning sword attack and
- Hold up move to use his special gun to attack the enemy when he least expects
OH and getting back to your question on which guns he uses
IWI Desert Eagle Mark XIX, Beretta 92FS Inox, Beretta Px4 Storm, Colt Model 1908 Vest Pocket, Glock 17, Heckler & Koch Mark 23 And ofcourse the famous dual katana blades.
For more details here is the link that explains the guns Deadpool uses