Here are some great ones that I've found for myself:
Humble Beginnings by forsillyfools.
How Artie Abrams comes to join New Directions, with appearances by Tina and Kurt.
Life May Not Be The Party We Hoped For by chuckney.
Artie Abram’s high school experience as told through five birthdays.
Plug Me In by chronic_lady.
Somehow, Puck and Artie have the wrong guitars.
Stage Left by unequivocally.
It sucks, doesn't it? Sitting stage-left.
But now I need more. Rec away!