Runner beans are probably the easiest thing to grow in your garden. They sprout very quickly and provide nitrogen fixing. They can clamber up poles and harvest very quickly.
Plants the benefits from beans are any that require lots of nitrogen to grow. So good companions are brassicas, like cauliflower.
Corn benefits from the nitrogen and also provides a trellis for the bean to climb up. Start the corn about one month ahead of the beans though. Corn grows slower than beans and needs to the head start so that quick growing beans have something to climb up.
This is our companion planting guide to beans.