If you have a pretty shady, wet area Mint is really hard to kill. And it’s super delicious in things like fresh spring rolls and tabouli.
For more sunny and dry-ish areas, lavendar rosemary and sage are pretty hardy, smell fabulous and can be used for cooking.
Also for sunny and dry areas, most succulents and cacti do very well, because you don’t need to water them very often. But they don’t do well at all, in areas where it gets cold.
Oxalis does pretty well. It’s a pretty ground cover who’s leaves look like clovers and they have pretty pink or white flowers. We have it growing amongst grassy areas that are kind of patchy (the grass is patchy) and you can also grow it in a pot.
Mother in Law Tongue seems to be growing in every yard in California, so they must be pretty hardy. They look especially dramatic if you put them up next to a painted wall of a lighter color than the plants, like in this photo.
Morning Glory Vines must do very well, because when you see them, they are all over the place (usually on a fence or a trellis).