I often have a couple of large pots of cherry tomatoes on my patio table, it keeps them out of the dog's reach so he can't wee on them 🙄
I actually buy them ready-planted, as a hanging basket, from my local garden centre and sit them on a big saucer on the table top.
I've also got strawberries in pots, and herbs such as chives.
I've also done French beans and peas in a big pot, with a support frame for them to grow up.
You could stand one on the patio at either end of the table.
Another idea would be to put some troughs, standing in a long tray, along the benches.
You could have some small bedding plants or bulbs, eg crocuses, in these.
If you oil the wood it will help to protect it.
Have a good look round your local garden centre and see what they have, it will help you decide.
Have fun!