At Elysian Fields you can find these ones:
Doing Their Best by peroxidelove
Summary: Set in S7 after First Date. On a day overlooked by her friends, Spike does his best to give Buffy something special on her birthday.
Strip Snap by Lilachigh
Summary: Buffy's 21st birthday party - she and Spike are sitting behind the sofa on the floor, playing cards. An innocent enough game, but the consequences are going to change them both for ever, when they are faced with making decisions that involve friends, enemies and the people they love the most. (this one starts with the B's b/day in the 1st chpt and then moves on from there. Warning: It has an NC17 rating and if you don't like Willow & Xander turning out to be hypocritical prigs then you may not want to read it.)
At Bloodshedverse there are:
Fluffy Presents by Angearia
Summary: Spike gets Buffy a present for her birthday. Fluff. Post-Not Fade Away. (short but very cute!!)
Gifts by Irishrose
Summary: Set in an AU Season 7. It's Buffy's annual birthday catastrophy. Or is it?
And at Fanfiction you could check out this one:
Pretty Bows by msu
Summary: Complete! Did anyone else miss the forgotten Buffy birthday epi? Then come and read my version of Buffy's bday bash with a little splash of fluffiness.
Enjoy, and have a great birthday!!
Sarah
