I just discovered this threat, and noticed quite a few cores missing.
For now, I'll just mention one.
Cloyster + Xerneas
Can anyone tell me when they last saw a good Cloyster offense, that didn't have a scarf Xerneas on it?
I can probably think of one, maybe two solid builds that don't include it.
Cloyster provides great support by laying down layers of Toxic Spikes, while a scarfed Xerneas demolishes most offensive threats.
An offensive core that just does so well against hyper offensive that I'm wondering why nobody has mentioned it yet.
EDIT: I think Cloyster + Mega Aerodactyl is an incredibly innovative and good core. No disrespect to my friend Lacus Clyne or her core what so ever when I say this, but let's be honest.
It gets outclassed by the Cloyster + Xerneas combination, as it fits a lot easier on teams/builds, takes up no mega slot, and has, bar the matchup vs Poison types, just the better presence overall.
I'm not saying the Aero + Cloy core should be removed, but rather that if that core got accepted, then this one should be for sure.
Cloyster + Mega Aerodactyl is really very different thing compared to this core, because Cloyster + MAero do a lot of different things including good offensive coverage, dual hazzard, avoid enemy set up, etc.
This core is worse than Cloyster + MAerodactyl in my opinion, because this core gets walled by Ho-Oh, a thing that most of the teams have to pressure