Yes it was/is that yobit forum - I don't know if it runs and how is it going - , then there's some crypto/altcoins forum the bounties not-in-correct form for bitcointalk were held there, then there's a few forums that were advertised also here .. I don't know how good are they doing, but I guess that some of them do exist.
Cryptotalk is already a fossil, it did gain traction in my school but it ended with nothing but air because the way they make money is unsustainable in so many levels. Also, I don't think that Bitcointalk is losing it's user base, there are new users in the forum that are slowly making merits and making a name for themselves, it's a slow burn so there's nothing to worry about.