That list includes all of the game's standard Trophies as well as those earned by playing its Freedom Cry DLC, but next to those entries are four Trophies for an as yet unrevealed multiplayer addition dubbed "Blackbeard's Wrath." The Trophies themselves don't give away the full scope of what the DLC will add to the game, but they do mention three new playable characters: The Orchid, The Jaguar and Blackbeard himself.
Those who have played Assassin's Creed 4 will know that the first two are fictional constructs created for use in the Animus, while Blackbeard was an actual pirate who, according to legend, was even more of a gnarled, terrifying figure than he is in the game. The Trophy listing for Blackbeard asks players to perform an aerial assassination then a pistol assassination within ten seconds with the character - an appropriately brutal homage to a man who routinely tied lit matches into his beard before combat simply because it looked spooky.
There is currently no word on when Blackbeard's Wrath might arrive.