The rotary engine, famously developed by Mazda, hasn't been used in a huge variety of car models throughout history. While Mazda has been its most prolific user, putting it in many of their vehicles over several decades (like the RX-7 and RX-8), the number of *different car models* that have ever used a rotary engine is relatively small. There were also a few experimental or limited-production vehicles from other manufacturers that utilized rotary engines.
Therefore, there isn't a single definitive number of car models. It's a much smaller number than the vast array of models powered by piston engines. We're talking dozens, not hundreds or thousands.
