Books:
http://fyeahfantasywriterunicorn.tumblr.com/ - Meme for genre writers.
http://fantastiquecollective.tumblr.com/ - Recommendations, crossovers and parodies.
http://neil-gaiman.tumblr.com/ - Official blog and the closest we get to Twitter-like interaction here in Tumblrland.
http://fuckyeahfictionalmaps.tumblr.com/ - Check the tags, exhaustive list of authors
Fashion:
http://fyeahnerdylolitas.tumblr.com/ - Check the tag list for frilly dresses and dragons.
http://dungeonsandfashion.tumblr.com/ - Dungeon and Dragons creatures and modern ensembles inspired by them.
http://whatwouldcerseiwear.tumblr.com/ - Inspired by Cersei Lannister. There are also sister blogs about Robb, Daenerys, Ygritte, Arya, Lyanna, Sansa, Jaime and Doreah.
http://dressingafantasyworld.tumblr.com/ - Fantasy costumes in visual media in detail.
http://sfffashion.tumblr.com/ - In-depth analysis of costumes and their symbolism in visual media again.
