There are lines of co-dom hypos that aren't compatible with recessive hypos ... and there are a couple of very rare recessive hypo lines that are not compatible with regular hypos ... but for the most part, hypos are like pastels when it comes to compatibility.

Axanthics are at the other end of the spectrum ... none of the lines are compatible so far ... and may never be.

It's looking more and more like all of the caramel lines are compatible, but not all have been tried yet.

That's just a quick shot off the top of my head.

-adam