Most games by 1C......
Namely..
Men of War - heavily underrated and mostly ignored game, but one of the best RTS I ever played. The level of detail is astounding, and gameplay is awesome. The cutscenes and voice acting are horrible, but who cares?
Panzers 1 and 2. Both absolutely great games but heavily underrated and ignored.
Act of War. The graphics and the level of detail were so high, that it rivals and often surpasses many games of today. Need proof? Just look at the MLRS in this game. The devs actually bothered to model most stages the rocket goes through as it leaves the launher. Further, you can actually observe the rocket exploding in mid air and raining down multiple explosive charges onto the enemy. Why the hell that game didnt catch on? I still dont understand....
Severance: Blade of Darkness. One of the best, and the most unique games ever, but heavily underrated and mostly ignored.
Command and Conquer 3, and in some ways Cane's Wrath(which sadly was a step back in many ways) So what that it was made by EA? They did an awesome job. Sure, it was the ONLY time they did an awesome job on an RTS because both the RA3 and C&C4 were utter garbage, but that has nothing to do with the gem that C&C3 was. It was awesome in every way, both single and multi player.
The original Sacred+Sacred Underworld Expansion. These were actually pretty good, unlike the garbage Sacred 2 turned out to be.