So I have enough csc left to get 4 of the challengers. I'm looking for challengers that give good EXP as some are better than others. Any that stand out?

If you've got a list of CS challengers you have already got, that would be really helpful since there are quite many of them and the risk of making a suggestion for those you have already got is pretty high.

I had only 2 when I posted this.

I now have Alba Frostholder Forj Leftover stuffed pepper Nsa the tainted Greasy joe Sandwort Cinthilocks Crithbolcan Vespus swarm Sentient porridge and The salad one (cannot remember its name)

Then you might want to pick up and all Extremely Hard and Impossible Challengers if your pet is already approaching Tier 12. Lower tiered challengers are good to buy only if you have more than one battle pet, because otherwise the EXP return would likely be low given the CSC you pay.

I thought the Bloody Summoning Altar was available all year I was intending to get that soon, if that is the case. I did want to get the mad scientist challenger so maybe that will be next, thanks for the reminder . Yes I do have other battle pets, much smaller though, I have a tier 9 and another tier 11 coming soon to my account.