Snow Kayaking for Northern states like MN NY MI OH VT NH WA
Sand kitsailing for SW US & HI volcanoes.
Coasteering anyplace in Hawaii alone, PR, Caribbean, NE US, CA, OR, AK alone for Fun or Norway.
All radical but defined by geographics alone for Use.
Coasteering can be the most widespread sport ever.
Sand kiteboarding maybe #2 with No Africa & SW US alone, Saudi Arabia.
Rest limited IE volcano sledboarding.

Viable Next Gen sports nonetheless