Because this topic never gets old. I'm always surprised how many questions I receive about protein and my hope is with this post I can answer some of them. (I've also written about protein before, see this post to find out how much protein you need).
Let me start by saying all whole foods contain protein -- even kale and bananas. Sure some whole foods have more protein calorie for calorie than others, but if it a whole food, it has some protein, which means as long as you eat enough calories (and those calories come from whole foods), you aren't going to be protein deficient (see this post for more info and resources).
Here is a list of plant foods that happen to be rich in protein... but remember, just because a food doesn't make this list doesn't mean it doesn't have protein. If it's a whole food it has protein, it's just not high in protein by comparison.
Soy (soy beans, tofu, tempeh)
Lentils & Beans
Spinach (100 cals spinach has more protein than 100 cals of steak!)
Seeds & Nuts
For a complete list, and handy info guide -- see this chart by the wonderful Vegetarian Resource Group.