These are in no particular order, just a bunch of things by people whose work I really like. 

Freyja has written some lovely little pieces of Highlander slash. Her site is here: Freyja's Fanfiction

Theban Band's award-winning fan art has to be seen to be believed, it's wonderful. Multi-fandom, multi-pairings. I particularly recommend their Lord of the Rings art. Go see it here: Theban Band

MacGeorge. There's a reason everyone recs her. Beautiful writing, brilliant characterization, and plots you can really get your teeth into. Dive into it here: MacGeorge's Madness

All of the gang at Taterville are well worth reading. New stories, new writers, just what the fandom needs. Go and enjoy something for every taste.

Becca Abbot writes in several fandoms. I've really enjoyed her Highlander and Andromeda fiction. You can find it here: Becca Abbot

Sleeps With Coyotes is a writer I can read again and again. Her Highlander fiction is some of the best in the business. If you haven't been there, do yourself a favor, seriously. It's all good. Go read it here: Blood, Love and Rhetoric

Kimberlee Gasper has written some truly incandescent Highlander slash and if you haven't met Randy and Michael yet, you're really missing out. Hot, hot, hot. Go check it out here: Infinite Passions