Nothing on a large scale, but I have quite a collection of non-slotted 'slot cars'. Ideal TCR from the 1970's and Tyco TCR (incompatible with Ideal) from the early 90's. 70's sets include glow in the dark cars and Vans. HO Scale - Instead of a slot there is a third rail that can change polarity to force your car to the other lane. So you can change lanes to pass. Most sets also had a 'jam car' that would run about 3/4 speed in one lane to force maneuvers (kind of a simlulated HRT).