Board Thread:Event Help/@comment-32650567-20170728211237/@comment-33728484-20170728220441

Some speculate that the new stage with PHY Goku is finally coming to Global, which would make sense since bringing him to SA20 is part of the challenge, and the new stage has a 15% chance of dropping the actual card. In that case, all the free characters from the events should be available (including the free Buuhan from the Buuhan event, for example), and you might also want to get Grandpa Gohan and other STR cards.

Here's the complete list of available characters: http://dbz-dokkanbattle.wikia.com/wiki/List_of_Freely_Obtainable_Units