It is! I found the page!

@XMillyX Ollivander was pretty strict about only making wands with his three cores, but other wand makers used many different cores. The elder wand I believe has a Thestral hair core.

@Andrade93 On the topic of Ollivander, he really only likes making wands a certain way, and we know that wands not made by him do use different cores and different woods, and as Jimbob mentioned it never is specifically said whether or not a wand can possess two cores, so perhaps in different countries they might have hybridized cores.

I'm a f***ing dumb***, sorry. Lol

You're not dumb, its just a rare HP question were there may not be an answer yet. We don't know of any cores with 2 cores, but we know other places do magic differently, so they could have two cores, but they equally might not.

I see

The elder wand has a thestral hair core

That's cool

I don't think so! I mean - if both unicorn and thestral hair have strong enough magic to give wizards the ability to cast spells with a wand, then it would probably get like a giant duel within the wand or something.

Nevermind, just my stupid theories

1. If your talking about cores then if you're getting them from Ollivanders, then the only core is unicorn hair

2. 2.If you're talking about patronuses maybe(like 0.000000000000000000000001% chance) there could be a mix of both

But different with wand makers, maybe wizards could fuse unicorn and thestral body part cores and use that