Underdeveloped Instinct by srin - I was really surprised by how much I liked this Arthur and how much the author got in his head. I suppose this is gen? If you squint really hard.
Cross You Off My List by strangeumbrella - this I mark for both rec and re-read frequently. I can't explain it, but the slight edge of cynicism in Arthur in this story is offset by the mellowness. I really like this look in Arthur's head as well.