I havent play against them yet, but in general they have high saves (+3 & +4) except the bloodreavers. So u will need rend to do some wounds. I used a Bastiladon vs Stormcast once and had some great results with the -1 rend/ 2 dmg shots. As always khorne will try to engage in close combat by turn 2 if possible with his Scullcrashers. You have to try do some wounds if possible, engage them first to have the initiative in this battle( you need something strong so u can kill at least 1 or 2 during your turn) or just try to kite them 1-2 turns,you cant avoid them reach you, in order to maybe kill one or egage without other unit of bloodbound to interfere. An other solid and in my opinion cheap choice is the skink starpriest. They have high 'to hit' characteristic in every unit, so the Starlight summon may save some of your models. You cant make a list to defend against all of their strong attributes playing a 1000 pts game. In a larger battle u can have more decent shooting. For a small fight try to build a scar vet on cold one from your start collecting, as you cant field 8 knights, and maybe invest buying a starpriest or just a priest for the save reroll. Using a second knight unit and some guard or warriorscan fill the rest points. If u play large battle, imo a bastiladon and a stegadon are solid picks. Using a unit of kroxigor, or a hord of warriors can do the work. Last but not least, dont forget our Sunblood. Decent abilities and a fair cost.
As i told starting this post, i never faced Khorn bloodbound. I give u advise from my battles vs stormcast and ironjaw (also elite armys).
i dont rly know how they play yet but i wonna be prepared. 
