How should we tag it? pictionaryultimateedition?
Tags with hyphens removed have generally been avoided. I'm not sure what the differences between the regular and ultimate editions are, but as Raven pointed out, that would be the most obvious tag to use if it is applicable.
If there are enough distinctions between the two games, my vote would be for either pictionary-ultimate or pictionary-ultimate-ed, as anyone searching for questions about the game will be able to easily identify it (especially with a helpful tag wiki).