Samm Diep demonstrated a couple of these drills to me earlier this year. These Oldie Goldies have been around forever…and for good reason. These drills develop your ability to move the cue ball relatively short distances with precision.
Classic 1 – Take ball in hand on the first shot, then pocket the balls in order starting with the ball closest to the rail.
Classic 1
Classic 2 – Take ball in hand on the first shot, then make the balls in the side pocket in order. Be careful, the cue ball doesn’t need to move very far!
Classic 2
Classic 3 – Take ball in hand on the first shot, then make the balls in the upper left corner pocket in order starting with the ball closest to the rail. Once you master this drill with the object balls located at O1, move the object balls to zone O2 and cue ball to C2.
Classic 3
Angle of Reflection 
I’m glad you liked these. I can’t take credit for them. They came from the PAT book:
http://www.pooltipjar.com/2010/06/ipat/
I love the PAT book. Their version of this drill is slightly different, with each ball one diamond closer to the short rail (so the 5 and 6 are basically on the rail). Of all their drills, this one in particular is really fertile — there are lots of ways to try to do it, and lots of ways to get it wrong (my favourite is to end a bit too far left on the shot to the 4, so I don’t have the angle to draw to the top side of the 6 on the cushion with the pace to get back down for the 5, but I can’t follow through without cannoning onto the 6). Always an interesting challenge.