Well, if you’re specifically looking for good stories featuring Grayson as Batman, I’ll recommend two:
The Black Mirror, which was written by Scott Snyder, and drawn by Jock and Francesco Francavilla (which is a criminally fantastic creative team). It ran in the last nine issues of the first volume of Detective Comics.
Also (sort of) by Snyder, I’d recommend Gates of Gotham, which is a miniseries. It was plotted by Snyder, and scripted by Kyle Higgins. It was drawn by Trevor McCarthy and Dustin Nguyen.
As for Dick Grayson stories in general, I’d check out Grayson, the DCYou series written by Tom King and Tim Seeley, and drawn by various artists, but mostly Mikel Janin, and the Rebirth volume of Nightwing, up until issue 50, where it goes totally off the rails.