Stretching can have a variety of benefits for runners when done properly. Before you try the folowing stretches, learn Why You Should Stretch After You Warm Up and read about the Most Common Running Injuries
For runners the calf, or gastrocnemius, muscle is prone to a calf pull or strain. Do this stretch after a good warm up and at the end of your runs. While it's similar to the Achilles tendon heel stretch, but by keeping your knee straight you focus the stretch on the calf rather than the Achilles.
The get used a lot in the running movement (partiularly downhill running). There are a lot of ways to attempt to stretch the quadriceps, but if you keep your hips stable, this is a good one to do while standing.
Because tightness in the low back and hamstrings is often related to muscle pain and stiffness in runners, stretch can help maintain good running form and reduce the risk of stiffness, pain and injury.
Runners sometimes forget to strech their upper body, but this basic shoulder stretch can be done quickly, so it's a good choice.
Runners can benefit from this advanced stretch, that is sometimes called the Pigeon Pose in yoga.
Another way to get the quads stretched out after a run is this kneeling quad stretch.