There are thousands of ornamental plants to use. I spend all day every day working with plants and there are thousands I have never worked with.
A pot hanging off a wall is unlikely to be insulated so the plant would most likely die outside. It can be about $25 each year to buy a colourful hanging basket that is a mixed planting of
trailing and flowering annuals.
If you wanted to get a little creative, you could buy the annual plants as small ones and plant it yourself each spring in a hanging pot. A few weeks after planting it will start to get bigger and by the late spring it should be looking good.
But since you said perennials... I would suggest having something trailing around the perimeter of the pot like Ivy, Thyme or Lantana (scented) and then a larger centerpiece like an Asparagus Fern, Scented Geraniums or Munstead Lavender that would go dormant in the winter, could possibly be cut back and will regrow (depending on the location).