the comonest ones on the market are;
busy lizzies, surfinnia, trailing fuchsias, trailing pelargoniums, trailing verbennas, bacopa.
hopt this helps.

or even tumbling tomatoes

I'm trying Scopia this year, as well, and Anagallis which is a bright blue. You could create a colour scheme of co-ordinated colours if you wanted to - pinks and mauves, or white with bright colours. Trailing Lobelia is a good one as well - it comes in pale or bright blue, lilac or a mixture.
You can also buy trailing foliage plants like Dichondra or trailing ivy which are a good 'foil' for the flowers.