is it possible to claim fork of coins in barterdex?
That is not possible yet. I assume you're talking about claiming bitcoin forks.
BCH and BTG are supported
How about for Bitcoin Diamond and Segwit2x?
bitcoin diamond does not have replay protection and we wont be supporting anything that creates such risks for people.
maybe if they fix it, we can reconsider.
the segwit2x is made by a totally unrelated team who put in 6 million coins of premine. I dont feel like supporting such nonsense