Maybe go the the Plant Database here, and enter a common name. That will bring up hundreds of varieties, dozens of species, and often multiple different genera (genuses?). One common name, many totally different plants.
Or you wanted to go the other way: one plant and many common names? Then you have to go into one or several entries for a species or variety, and look at other common names for that kind of plant.
That way is harder! I searched on "Marigold", and then "Daisy". There were so many species and genera that it took some scrolling to find several of the same species!