Every guide here names varieties bred for containers and gives a minimum size in gallons — so the list is sorted by what actually earns its pot, not by what photographs well.
What's different about vegetables in pots
A raised bed buffers your mistakes. A 5-gallon pot doesn't. Three rules cover most of it: size up (the chart is the minimum, not the target), feed little and often (nutrients wash out with every watering), and mulch the surface so July doesn't cook the roots.
What to grow first
Not tomatoes. Lettuce, bush beans, radish and chard forgive nearly everything and crop within six weeks. Tomatoes, cucumbers and potatoes are the big wins of year two — they reward you once you've learned how fast a pot dries.