One of the new features in Minecraft 1.11 is woodland mansions, these structures generate very rarely in roofed forest Biomes tens of thousands of blocks away from the spawn. Finding woodland mansions will either require woodland explorer maps which can be purchased from cartographer villages with emeralds or by using the '/locate Mansion' command. Woodland mansions generate randomly and their structures will vary, they will however all have certain things in common, they will have 2–3 floors which will have a variety of different rooms and it will have a cobblestone foundation underneath the entire structure. The top floor is always a bit smaller than the floor or floors below and there will be a large foyer and a winding maze of corridors. Not all of the rooms in woodland mansion are readily accessible, you will find some may have sealed entrances while others may have no entrances at all, there are over fifty different types of rooms and they are all randomly generated. The video below is a quick tour of every single room you can find in a woodland mansion.
Listed below in no particular order are some of the best seeds currently available that feature a woodland mansion along with its coordinates.
Room of Diamonds
Seed: 2708143789541548520
Mansion Coordinates: 10627, 88, -18579
Secret Room Coordinates: 10666, 90, -18580
Old Fashioned Near Spawn (and an Underwater End Portal)
Seed: -4589128118707775879
Coordinates: 200, 73, 533
Extreme Waterfront
Seed: -8918806821556526521
Coordinates: -760, 2960
End Portal and Mooshroom Island
Seed: 4388092437280786657
Coordinates: -776, -1736
Extreme Hills Mansion
Seed: 455183159361683197
Coordinates: -423, 80, 41
In case you're also looking for a Desert Temple
Seed: 6417841594308614589
Coordinates: 1544, -1159
A Savanna, a Ravine, a Blacksmith, and a Nether Fortress
Seed: 7056697421514564835
Coordinates: 417, 65, 591
Two Desert Temples
Seed: 3585663767566414981
Coordinates: 856, -776
Here, have some monsters.
Seed: -8567493892092483216
Coordinates: 293, 139
Oceanside Chicken
Seed: -528168294321987409
Coordinates: 248, 70, -680
Fight Club
Seed: 426309126
Coordinates: -14910, 66, -1005
Want some Village neighbors?
Seed: -1253292870183042340
Coordinates: -696, 70, 392
Even more close to spawn fun
Seed: -671333979171566709
Coordinates: 330, 620
Village and a Flower Forest
Seed: 4349021618365212927
Coordinates: -1912, 3048
Obsidian and Mineshaft
Seed: -3810461314851024308
Coordinates: -688, 64, 1934
Spawner City and Lava Room
Seed: 6749295965849649575
Coordinates: 1889, 115, 2195
Books and Mineshafts
Seed: -5744779235347951970
Coordinates: -101, 71, 265
Village Spawn and Desert Temple
Seed: -657609829779966653
Coordinates: 408, 264
Village Spawn
Seed: -5217747434466194118 (1.11.2)
Coordinates: -728, -5640
Waterfront and Near a Village
Seed: 8197364447347830626 (1.11.2)
Coordinates: -510, -800