TilenB
Strata Poster
I think there's a good reason only one of these was ever built. The spinning (or rather turning) mechanism hasn't been in use since soon after it opened and while this is purely anecdotal, considering the fact that it was down for maintenance for about 9 months at the time I visited, doesn't exactly make it sound like the ride is particularly reliable even when you take the spinning mechanism out of the equation.Vekoma Big Air - https://rcdb.com/8656.htm
That massive U shaped shuttle coaster where the cars still spin at the top of the spike. I don't even know if its any good but am curious to find out.
Another one that I haven't seen mentioned yet is Vekoma Stingray. A compact flying coaster that received mostly rave reviews. Only one has ever been built, but it sadly closed down with the park in 2018. Hopefully it will reappear somewhere at some point, but the model seems to be pretty dead now.