Historically, not in the last year (since Hunter flat out did not actually receive many cards over 8)
Kathrena Winterwisp/Call of the Wild/Oondasta/Charged Devilsaur/(probably)Bonemare/(probably)Ragnaros
If you broaden it to 7 and above, there are many more.
Call of the Wild in particular imo is very similar to Zixor Prime. It sets up a threatening board that has to be dealt with. In fact Zixor Prime is much higher in tempo than Call of the Wild (Call did 5 damage+buffed your other minions, Zixor Prime does 16 damage to board. Yeah okay CotW has Charge on the Huffer, but this has much more impact on board. And on the following turn, you have 12 damage on board+up to 4 more damage from the Leokk buff. This just gives you 16 by itself.). And when Call was 8 it was literally in every freaking Hunter deck that existed.
Yeah you have to play it twice, but honestly Hunter has received quite a few tutoring effects. Diving Gryphon allows you to get Zixor/Zixor Prime out really easily. Then there’s the aforementioned Scavenger’s Ingenuity. And then there are tools like Nine Lives which allow you to double-dip on the card.
The board impact is there. The potential for it to gel with existing cards is there. Why the heck wouldn’t it work?