Well, while it may hard, and extremely rare for it to happen. You could always try the wonder trade. See, because if you’re like me, and don’t have anyone near you to play/trade with, or don’t have multiple consoles to trade amongst yourself with, this is your only way. I tried the wonder trade, and actually just got a mew. Which shocked the hell outta me. Seeing as how I just use the wonder trade to fill my Pokédex. So yeah, try it out.