What zone are you in? And how hot are your summers?

I am in zone 9 and we average around 90 with high humidity.

A few ideas: sweet potato vine, creeping raspberry, strawberries, new zealand spinach, sorrel, thyme and any number of other low-growing herbs.

Sweet potato is probably the most ornamental of the above since it is available in several colors. It prefers full sun, but at a low latitude part sun would probably be fine.

Creeping raspberry is probably the hardiest of the above.

Pineapples and dwarf eggplants do well for me in zone 10.