I like emberguard! Easily one of the most impactful legendaries from the current glint shop rotation.

Lord Thalanor is great but less versatile because of the high mana cost and you probably wanna pair it with Tofu, right?

And of course the other you mentioned are incredibly strong too, especially Mantaroth as a tank!

Anyway, I also really like Barashkukor from the death splinter. 13 mana but it can take out some taunt monsters with one hit which is pretty funny and it's amazing with Lorkus too.