ODST- Halo 4 Beam Rifle
Blue- Halo Reach DMR
Field Marshall- Two regular Plasma Rifles

Mostly everything in the image is based on Reach's assets, unless asked specifically to be from a different game. The things that aren't based on Halo Reach (just to show you guys how much research I put into these sort of images):

- Halo 4 Jackal (Reach Needler, Reach eyepiece, and a Halo 3 shield)
- The Grunt's undersuits are lightly based on the Grunt Rangers from Halo 4
- The Grunt's sleeker methane tanks are based on the Reach Covenant jump packs
- The Marine-helmet Grunt has a Halo 2 breathing apparatus
- Halo 3 Jackal Sniper (Halo 3 Beam Rifle)
- Halo 3 Elite Minor (Halo 3 MA5C AR)

I appreciate the type of Halo images that take the visuals from a bunch of different sources and make them work cohesively.