Large slopes or gardens with severe gradients can be a bit of a challenge.
Exposure, poor soil quality, accessibility and maintenance are usually issues.
These are actually the conditions that so many plants thrive on, like herbs, grasses and meadow perennials. In good nurseries there is a wide variety to choose from.
Ideally, the smaller the pot size the better the plants adapt to the situation and produce a good root system deep into the ground. Many will self seed and fill empty spaces. Eventually the slope will be covered, and maintenance will be little to none.