a MLP X Pokemon idea that needs help

I already have 3 ideas of MLP X Pokemon crossover ideas, however one of them needs some help

This idea is putting Legendary and Mythical Pokemon in Equestria through its most important events, such as the past of the Crystal Empire, Nightmare Moon, Discords first reign, ect.

so I wanted to ask you guys, which of the legendary and mythical pokemon should be where and when? I wanna hear your ideas for this idea