As at least some of you will already know, the yellow corehound (Gomegaz) is actually a combination of textures from two different corehound colours.
Corehounds have a main body texture, and also a coloured glow/overlay skin that is transparent. Combining the green body with the orange glow and flames from the standard corehound gives us Gomegaz. But, the same technique also allows for a couple of other looks, which I've just added to our unused appearances database:
Yellow-orange:

This bright and cheery corehound combines the body texture and flames from the orange corehound with the green glow from the fel one. I really love this colour.
Green-yellow:

This one is actually identical to the Gomegaz one, but with green flames instead of orange. The different flame colour makes quite a difference to the overall look, and it looks good.
It's also possible to give green flames to the bright orange one, but the look doesn't really blend as well so I decided not to add it.
I wish we had one or two more basic core hound colours, as the number of possible shades would increase exponentially!
Thanks for Marlamin and Deamon for fixing particles on wow.tools' model viewer, which allowed me to get decent shots of these. I'd been hoping to add them for some time.