I’m a long time motorcycle trials rider. In the mid 1980’s thru the 1990’s "trialsin" as the Europeans call it got pretty popular here in the US. At local events there would often be a bicycle trial after the motorcycle trial. These events were all off road but used natural and man made obstacles. The two most prevalent bikes were the Monty and the Maverick. There was the occasional Ibis as well. I believe the Monty is still available
I may be wrong, but I think the sport has almost completely gravitated to the urban environment. After all theres an awful lot of sweet obstacles to ride in the city.
The skill of these riders is absolutely phenomenal making trials a really great spectator sport.
FWIW, that’s my experience albeit a bit outdated.
Bryan