There is actually an old thread, which can be found here, listing almost every cosmetic fansite that has existed over the past 2-3 years. However, many of the fashion blogs have fizzled out since late 2012 for various reasons, leaving that thread mostly useless. Don't get me wrong, you can still browse through them for wonderful outfit ideas...provided their domains haven't expired or blogs have been deleted. Also, the OP of that thread hasn't updated the listing in a very long time.
Figured I'd start a fresh thread with a list of active blogs in alphabetical order. And by active, I mean an update posted within the last six months of this post to account for breaks, real life, and the like.
Cosmetic LOTRO -- http://cosmeticlotro.wordpress.com/
The Elven Tailor -- http://theelventailor.blogspot.com/
The LOTRO Stylist -- http://lotrostylist.wordpress.com/
Material Middle-earth -- http://materialmiddleearth.blogspot.com/
So Long, and Thanks for All the Fashion -- http://solongandthanksforallthefashion.wordpress.com/
The Starry Mantle -- http://starrymantle.wordpress.com/
Style of Middle-earth -- http://middleearthstyle.blogspot.com/
Wandering Around Arda -- http://wanderingarda.wordpress.com/
Even though it isn't a blog per se, you can also find some outfits on LOTRO Players -- http://lotroplayers.mymiddleearth.co...lotro/fashion/
If I've missed one that I don't know about, please reply here and I'll get it listed