Given a day I can give you 100 stocks that are rising by being pumped only, given a week I'd wager a 1000
could be named,
In many cases there is no demand to buy.
Collusion is proven by the fact that decent volume sales in blocs are met with low volume buying instantly after the blocs finish, that takes knowledge that the seller is done, i.e. it's almost certainly the same entity. They line'em up and rake'em off, then form a new line.
Ironically some issues being so totally void of value results in a large short position and thus the ability to manipulate.