This weeks issue of Shonen Jump has revealed two new fighters for J-Stars Victory VS. The first is Tsunayoshi Sawada from the recently completed Reborn! series. In addition to Tsuna, we also have Tatsumi Oga from Beelzebub. Both of these characters are playable and the scan also revealed Kagura from Gintama will be a support character.
While none of these characters are surprising, J-Stars Victory VS is still missing several extremely popular series. This will probably change as we get closer to release, though hard to say given all the newer characters appearing.