How do you get all Pokemon without a event?

I've looked for how to get Pokemon without events, but I'm 100% sure that you can only get Pokemon like Shaymin, Darkrai and Arceus is with an event OR with an AR ( Action Replay) or an R4, which is selling quite cheaply for $28. Hope I helped ----Wolf_boy_Tsukuyomi_ ^_^
Can get REGIGIGAS and other event Pokemon like darkrai online at

other event Pokemon on there aswell check the other items