Tokowha by Nyssa---http://lotr.adultfanfiction.net/story.php?no=19840 ---Unfinished WIP, Sean/Karl. I liked the matter-of-factness both Sean and Karl had toward sex at first in this story. Seemed very "guy". I'm sorry it was never finished.
Two of a Kind and Ante Up! by Mereiswen---http://lotr.adultfanfiction.net/story.php?no=21903 & http://lotr.adultfanfiction.net/story.php?no=24087 ---Viggo/Karl. Viggo and Karl play strip poker, and Karl gets an eyeful that he can't forget. Karl chanting "Here a Viggo, there a Viggo, everywhere a naked Viggo" to the tune of Old MacDonald made me laugh. And there's hot sex!
All Tomorrow's Birthdays and Different Tastes by Lobelia ---http://www.geocities.com/lobelia321/fics.html ---Karl/Dom, John Noble/Barnard Hill/Karl/Dom. Very strange pair of tales, but I enjoyed the trip. Karl and Dom seem sort of out of character here, but for some reason Karl's mix of stubborn optimism and self-deprecation got to me.
Wish Me Joy by akstinger---http://www.fanfiction.net/s/2450853/1/ ---Eomer/Legolas. Some stories have a cliche---the OTP is split up, a nice guy comes along who helps one half of the pair and ends up getting his heart broken when the OTP gets back together. Eomer has the nice-guy duties here, but the author actually lets the nice guy finish first this time.
Right to Remember by Mariole---http://www.fanfiction.net/s/3063519/1/ ---no pairing. Eomer is a supporting character here---literally, as he helps Frodo deal with the memories of his ordeal in the hands of the Orcs. A lovely meditation on the effects of trauma and war and how sometimes a stranger is the best confidant you can find.