Here are 40 seeds with all 36 biomes required for the advancement "Adventure Time" including Mushroom Island, Mega Spruce Taiga and Ice Plains Spikes within a world border of 4096 blocks (-2048,-2048 to 2048,2048). Two of them even with a woodland mansion!

Thanks to the Amidst project and sZPeddy!

preview maps at imgur.com

V=Village, I=Igloo, D=Desert Temple, J=Jungle Temple, O=Ocean Monument, W=Witch Hut, S=Stronghold, M=Woodland Mansion

 -55414997194881801; 8V 4I 1D 4J 1O 2W 1S 1M ( -792/ -904); 0.43% Ice Plains Spikes; 22.05% Ocean; woodland mansion! 378209395352473212; 6V 8I 1D 2J 1O 2W 2S 0M ( 9592/ -4808); 0.21% Ice Plains Spikes; 24.32% Ocean; -491676171880828995; 9V 6I 3D 4J 1O 0W 2S 0M ( 9448/ -3512); 0.01% Ice Plains Spikes; 25.71% Ocean; crazy Savanna Plateau M spike y=193 near spawn -755319513842796464; 5V 0I 0D 3J 3O 3W 2S 0M (-21288/ 20968); 0.34% Ice Plains Spikes; 31.89% Ocean; -974517182536699962; 7V 1I 4D 1J 3O 2W 1S 0M (-11048/ 4408); 0.24% Ice Plains Spikes; 21.23% Ocean; 1299445876672779963; 13V 5I 7D 1J 7O 1W 1S 0M ( 20712/-18744); 0.78% Ice Plains Spikes; 43.40% Ocean; spawn in village with 3 diamonds 1416131600849806535; 5V 4I 0D 4J 7O 1W 3S 0M ( 10792/ -3576); 1.18% Ice Plains Spikes; 40.27% Ocean; -1486597308561310039; 7V 2I 5D 7J 1O 3W 1S 0M ( 5704/ 9272); 0.27% Ice Plains Spikes; 19.86% Ocean; 1669283483338956431; 5V 3I 1D 1J 10O 4W 1S 0M ( -3080/ -872); 0.24% Ice Plains Spikes; 53.42% Ocean; 1853607272398192960; 7V 6I 4D 2J 5O 2W 3S 0M ( -1704/ 8152); 0.46% Ice Plains Spikes; 32.69% Ocean; -2186106134841955739; 10V 8I 4D 3J 5O 0W 1S 0M ( 6920/ 152); 0.56% Ice Plains Spikes; 33.93% Ocean; 2220880635968255999; 4V 9I 3D 2J 2O 1W 2S 0M (-11192/ -2088); 0.71% Ice Plains Spikes; 19.83% Ocean; 2238482112631925194; 5V 1I 3D 0J 4O 0W 1S 0M ( 15624/ 16936); 0.45% Ice Plains Spikes; 53.79% Ocean; 3474750793791788497; 10V 3I 4D 1J 1O 4W 2S 0M ( -8344/ 10600); 0.20% Ice Plains Spikes; 12.95% Ocean; -3610886374948718390; 2V 4I 2D 1J 2O 1W 3S 0M ( 17256/ 5416); 0.14% Ice Plains Spikes; 37.21% Ocean; spawn on island without trees 3646770445914740399; 0V 3I 0D 6J 0O 4W 2S 0M ( 7912/ 10824); 0.20% Ice Plains Spikes; 36.89% Ocean; -3729218462379209020; 6V 3I 0D 6J 0O 4W 2S 0M ( -1992/ 2984); 0.43% Ice Plains Spikes; 43.63% Ocean; 3951106291677499945; 10V 2I 2D 3J 1O 2W 3S 1M ( 536/ -936); 0.17% Ice Plains Spikes; 26.08% Ocean; woodland mansion!, spawn on island without trees 4042240345965771856; 8V 2I 5D 4J 3O 3W 3S 0M ( 5960/ 6776); 0.27% Ice Plains Spikes; 20.26% Ocean; 4798544232576907347; 10V 3I 3D 1J 2O 1W 2S 0M (-16392/ 9320); 0.46% Ice Plains Spikes; 32.50% Ocean; -4942920632027724675; 1V 3I 0D 1J 6O 0W 3S 0M ( 21208/-24936); 0.14% Ice Plains Spikes; 52.63% Ocean; 4943560139257792518; 4V 3I 0D 5J 0O 2W 1S 0M ( 1768/ -6312); 0.31% Ice Plains Spikes; 11.18% Ocean; -5150484020392416516; 5V 4I 6D 2J 6O 0W 1S 0M (-13480/ 15656); 0.42% Ice Plains Spikes; 43.45% Ocean; -5402673605257231442; 9V 0I 1D 3J 4O 1W 3S 0M ( 3496/ -9640); 0.19% Ice Plains Spikes; 42.08% Ocean; 5841794849523091365; 4V 5I 4D 0J 2O 1W 2S 0M ( -4760/ 6872); 0.46% Ice Plains Spikes; 24.67% Ocean; -5870034195416519391; 5V 5I 1D 4J 3O 3W 0S 0M ( -7624/ 26184); 0.04% Ice Plains Spikes; 41.82% Ocean; unovergrown jungle temple near spawn 6462466405470433409; 7V 10I 1D 0J 0O 3W 3S 0M ( -1752/ 14648); 0.31% Ice Plains Spikes; 16.39% Ocean; 6519449351705508869; 3V 3I 2D 3J 4O 0W 1S 0M ( 6984/ -9896); 0.34% Ice Plains Spikes; 48.19% Ocean; -6838735121102853161; 6V 4I 0D 0J 2O 1W 2S 0M (-13288/ -5944); 0.30% Ice Plains Spikes; 23.83% Ocean; 7088896416840668197; 3V 1I 1D 4J 4O 3W 1S 0M ( 648/ -3432); 0.30% Ice Plains Spikes; 39.71% Ocean; 7618654116148779787; 5V 1I 0D 3J 0O 2W 2S 0M ( 9400/-16312); 0.45% Ice Plains Spikes; 21.31% Ocean; 7658306913263741137; 7V 2I 3D 3J 1O 1W 2S 0M ( 19784/-21224); 0.31% Ice Plains Spikes; 16.22% Ocean; 7697610728786725808; 7V 6I 3D 2J 5O 1W 2S 0M (-16568/ 11816); 0.22% Ice Plains Spikes; 31.17% Ocean; -7750830373751606528; 7V 3I 1D 3J 2O 1W 2S 0M ( 8184/ -3272); 0.02% Ice Plains Spikes; 29.41% Ocean; -8155751749042674775; 2V 3I 2D 2J 6O 4W 2S 0M ( 4088/ -9576); 0.02% Ice Plains Spikes; 36.29% Ocean; 8483303985309521748; 7V 3I 4D 3J 1O 2W 3S 0M ( -664/ -3320); 0.69% Ice Plains Spikes; 34.20% Ocean; -8559364381345418738; 3V 5I 0D 1J 4O 2W 2S 0M ( -4968/ -952); 0.40% Ice Plains Spikes; 40.03% Ocean; -8664817670574595963; 8V 5I 2D 1J 1O 2W 3S 0M ( -6264/ -3624); 0.53% Ice Plains Spikes; 19.05% Ocean; 9083251511796234041; 3V 3I 1D 2J 2O 2W 1S 0M (-18920/ 12184); 0.17% Ice Plains Spikes; 25.90% Ocean; 9190483883666827439; 2V 9I 0D 0J 3O 1W 3S 0M ( -9496/ -1160); 0.57% Ice Plains Spikes; 43.50% Ocean;