As a reminder, here are the general molds for the 5 types remaining:
Rock- Oh lawdie. Slow as fuck, and almost all Physical. Nice attacking type, so if we really wanted to break the mold, we would pair it with some shitty typing for coverage. (I'm looking at you Steel/Psychic/Bug/Dark/Grass)
Electric- Fast and special. Usually frail, unless the second type's mold changes it (See Magnezone/Lanturn). Only two physical electrics, and one's UU and the other one is bottom OU. Easy enough, provided we give it a polar opposite secondary typing (See Dragon/Rock/Fighting)
Steel- Slow, defensive, and poor attacking stats, unless a secondary type has a different mold. (See OU Steels.) Has a boatload of resistances, but shitty attacking typing unless backed up by an offensive secondary type (See OU Steels again.) Very good typing to break a mold with.
Dragon- High Physical attack, usable Special attack for Draco Meteor. Medium to Fast speed, with considerable bulk for a class of sweepers. However, there's only one dedicated support dragon, so there's room here to break a mold.
Fighting- Lets get physical, physical! Bulky, and with the exception of the rare SpecsLuke or even rarer SpecsApe, all physical. They're also Low-Medium speed generally, with Infernape being the fastest at 108, and Primeape coming in next at 95. This would be an easy mold-break, because it's the most clear-cut mold.