Useing an avian theme I rather like "A Plump of Ebikes",(because we're all quackers)
it certainly follows my thought train as I regularly refer to the sportive riders as "Flocking cyclists" obviously because they flock together
Plenty more spring to mind
A Plush,
A Pleasure,
A Comfy,
A Charge,
A Chuckle,
An Alternative of Ebikes
or An Oddity of Ebikes.....you don't often see them riding in groups
I don't have any negative nouns as I see Ebikes as a good thing, I think the OP is looking from the "ordinary" persons perspective.
Just thought of
An Enlightenment of Ebikes