Q.Good Plants/Flowers
We have several 1/2 pots. The type that are meant to look like 1/2 is buried in the ground. They sit at a 45 degree angle. Nothing we put in them does well. Would like some colorful suggestions.

I would try ground cover type plants, they have the natural growing pattern that would more easily work in this type of container.
Here are some links that will help you select something that suits your garden.
https://www.gardeningknowhow.com/special/shade/ground-covers-for-shade.htm
https://www.gardeningknowhow.com/special/xeriscape/drought-tolerant-ground-covers.htm