You know, I just want them to flesh out all the type combinations... Some Noteable ones:
Normal/Ghost: Kind of OP, but on the right move set, etc, lots of fun.
Fighting/Dragon: Raptor Pokemon, catchable only in Tall Grass Hoards. (Lol, but for serious)
Pure Flying: As a non-legendary. (Perhaps an Eevee evolution as some kind of Tornado looking thing, Breezeon lets call it, with a similar spread to Jolteon, but Att instead of Sp. Att, give it Mega Pincer's ability too...)
Normal Legendary that's useable: Jackalope pokemon. You could put Plates on it that ADD a type to it (IE: Normal/Plate type), and an attack move similar to Arceaus', but it would be dual typed like Hawlucha's signature move (Thus nerfing the Ghost/Normal combo...)
Fire/Electric: The Firestrom Pokemon. Has Levitate, awesome Speed and Sp. Attack, crap Defences.