The Training Series by luckyrory7
It's pretty much a H/D get together fic during auror training. What I really like about it is the characterization that goes a step higher with every installment. And its not just about the way the author writes but also the bits and pieces that are left unsaid. If you read between the lines, there's a lot more going on under the surface which is what makes it such a lovely H/D read.