All Features for Pokemon Legends: Z-A's Mega Dimension DLC Confirmed So Far

Pokemon Legends: Z-A has been out for almost two months now, and it's already getting its Mega Dimension DLC very soon. This is a paid expansion that will allow players to go through new content like quests and Rogue Mega Evolution battles, as well as catch more returning Pokemon and unlock some new Mega Evolutions. Even though multiple trailers have been released so far, it's quite likely that Pokemon Legends: Z-A's DLC has not shown everything it has to offer just yet.
Pokemon Legends: Z-A's list of returning DLC Pokemon leaked weeks ago, and while it hasn't been confirmed in its entirety, all the critters featured in the trailers were on that same list, including that of the 19 new Mega Evolutions coming with Mega Dimension. On top of that, players will have brand-new mechanics to engage with in a new baking minigame involving Hoopa and a character by the name of Ansha in order to explore the new setting of Hyperspace Lumiose.
Pokemon Legends: Z-A's Mega Evolutions are front and center of the game's core experience, so it only makes sense to double down on them with the DLC. According to leaks, there will be 19 new Mega Evolutions in the DLC, which include:
Since the revealed Mega Evolutions were all on the list of leaked new Megas, it's safe to assume that these will mostly be correct when the Mega Dimension DLC is released. Mega Heatran and Mega Darkrai in Pokemon Legends: Z-A were first leaked soon after launch alongside Mega Zeraora, thanks to their Mega Stones appearing in a list of removed items. Likewise, after Mega Lucario Z, it makes sense to give popular Pokemon like Absol and Garchomp a new Mega.
Based on the leaks, which came from a datamine list of scrapped data for some Pokemon, Pokemon Legends: Z-A's DLC will include 138 returning Pokemon total. These are:
Several Pokemon from this list have also been spotted in official trailers for Pokemon Legends: Z-A's Mega Dimension DLC. It's unclear if all 138 will indeed be featured, and whether they will all be catchable when the DLC launches. Considering the Diancie and Mewtwo events in Pokemon Legends: Z-A, it's likely that some will be post-launch.
The many leaks for Pokemon Legends: Z-A's new and returning DLC Pokemon, as well as the recent Pokemon Gen 10 leaks, have revealed no features or story elements. However, one of the official trailers for the DLC did show fans what to expect on December 10:
While unconfirmed, it's likely that there will be new Research Tasks from Mable. Pokemon Legends: Z-A's Shiny Charm requires most Tasks to be completed, but there is a surplus of points for leveling up that are not applied in the base game.