If the Caspian Sea exodus is true then not many significant Black Sea units can do it with a published depth available of 3.7m and probably less in reality
The Kilos, Grishas, Krivaks, Steregushkiy, Admiral Grogorovichs, Aligators and the fleet ilers certainly can't, the Ropuchas would be marginal with a 3.6m draft.
Not much of significance left but coastal missile boats and small landing/patrol craft.