Revell of Germany is a major kit re-boxer in 1/35 scale. Although many of their Bundeswehr (West Germany Army) kits are originally theirs, the vast majority of their kits are someone else's with new decals and perhaps some retooled items on the sprue.
Among the compaines that Revell reboxes are #1 Italeri; #2 Dragon/DML; #3 Esci. They've also reboxed some eastern European kits like the GAZ-66.
Most of RoG's WW2 German armor are Dragon kits. Also most of their modern Soviet/Warsaw Pact are Dragon kits. Their WW2 US/Allied and modern US/NATO kits are Italeri kits.
Their M60A3 is an old Esci kit and their M88A1 is the AFV Club kit. The M34 2½ ton tactical truck and Jeep set are the old Monogram kits.
There are probably other manufacturers out there that I missed.
I agree that their 1/72 scale kits are the best out there, but some of their kits are reboxed Hasegawa kits. They also reboxed some of the old 1/76 scale Matchbox kits along with their own vinyl soldiers. They've recently started reboxing many of the old Matchbox kits without soldiers too.
Again, RoG is a mixed bag due to the fact that they draw their kits from all over. Chances are that if someone makes a model of the same or similar model that is in a Revell box, it is probably a rebox of the other company's kit.