Thought this was interesting..
Within the file system of Mario Kart 8, there is a list of tracks and their streaming audio.
When the last DLC pack went up, there were 8 tracks contained in the pack, but actually 13 entries.
The first 8 were in that pack, but the remaining 5 were not and are likely to be tracks in DLC Pack 2.
The following are the ones we got:
And these are the ones listed but we never got:
GC_YOSHI_CIRCUIT = GCN Yoshi Circuit
SFC_RAINBOW_ROAD = SNES Rainbow Road
WII_WARIOSMINE = Wii Wario's Gold Mine
WU_DRAGONROAD = Dragon Driftway
WU_EXCITEBIKE = Excitebike Arena
WU_HYRULE = Hyrule Circuit
WU_ICEPARK = Ice Ice Outpost
WU_MUTECITY = Mute City
So I think we can comfortably guess that DLC Pack 2 will include Neo Bowser City from the 3DS and Baby Park from the Gamecube as well as the Animal Crossing track.
3DS_NEOBOWSERCITY = 3DS Neo Bowser City
GC_BABYPARK = GCN Baby Park
WU_ANIMAL = Animal Crossing
WU_METRO = ?
WU_WOODS = ?
But what has me really excited is WU_METRO. Metro..... id? I live in hope!