Check out http://www.golemgame.com/
and
The Crazy Machines series is a lot of fun too. Also, Rigs of Rods is another one like BeamNG that uses soft body physics. Might even be the same devs? Not sure.
The Red Faction games have the coolest destruction physics I've ever seen and are incredibly fun. They're technically shooters I guess, but all I do really is the destruction challenges and run around destroying structures in various ways.