There will be two new Eeveelution in the dlc. First one's name is Galeon and it is a flying type that has fans on its body and blows air in order to glide. It cannot fly, but it will gain a Gigantamax that does.

Second dlc has Guardeon which is a play on the word Guardian. It's a dragon type with an armored motif and it will have an extremely difficult evolution method. Something that may put Feebus in Ruby and Sapphire to shame.