association of plants

I am looking for a list of plants (vegetables) which have a good relation
among each other

E.g. The tomato goes well with the carrot and onion, but should not be
planted next to potatoes or beet root.

I would like to know especially on behalf of potatoes, cauliflower, cucumber
and onion.

Is there anybody out there who could help me herewith?

Thanks in advance,

Willem Steunenberg