Benefit Cosmetics' POREfessional Matte Rescue ($28 for 1.6 oz.) is a mattifying gel with an invisible finish. Diamond powder, known for its soft-focus, pore-blurring effect instantly minimizes pores. It leaves pore size diminished, as well as shine and the appearance of fine lines.
Since this gel is water-based, it feels so much more lightweight than the original POREfessional, and there's much less wait time before applying makeup. While this isn't technically a primer and is recommended as a pre-primer base, I've been using it as one and have been loving it. If you love what POREfessional does for you but you feel like it's a little too heavy, especially if you don't do full-face makeup everyday [I opt for a BB cream and translucent setting powder], give this a try!