Here is a table that lists information on some common plants.   (most of this was compiled mostly from 'Square Foot Gardening')

Alliums: Onion, Garlic, Chives

Helps 

 fruit trees, nightshades, brassicas, carrots

Helped by 

 carrots

Avoid 

 beans, peas, parsley


Corn

Cucumber

Herbs

Some common herbs to try: Thai Basil, Sweet Basil, Oregano, Sage, Rosemary, Italian Parsley, Cilantro

Lettuce

Onion, Garlic, Chives (Alliums)

Helps: fruit trees, nightshades, brassicas, carrots.

Helped by: carrots

Avoid: beans, peas, parsley

Peas (Edible Pod - Sugar Snap)

Plant early (February).

How to keep them from getting yellow when it gets warm in the spring?

Pepper

Tomato

Keep sucker vines pruned, and keep branches pruned to prevent overcrowding around other plants.

Prune bottom 12-24" of branches to keep splashing soil from getting on leaves and to provide better air circulation.  (said to help prevent diseases)