Cardiff Roller Collective was created in 2010.
The noun 'roller coaster' has no standard collective noun since most roller coasters are not in a group. However, a collective noun is an informal part of language. Any noun the fits the situation can function as a collective noun; for example, a scream of roller coasters, a maze of roller coasters, a park of roller coasters, a tour of roller coasters, etc.
Cardiff Railway was created in 1897.
Cardiff Marathon was created in 1981.
Cardiff Blues was created in 2003.
Radio Cardiff was created in 2007.
Cardiff Devils was created in 1986.
Cardiff Demons was created in 1997.
Cardiff Redhawks was created in 2004.
Cardiff Bus was created in 1902.
Cardiff RFC was created in 1876.
Cardiff University was created in 1883.
Cardiff Rose was created in 1976-05.