Many Amaryllis selections have been made, and the species has also been hybridized very heavily with related genera for more than a century. To learn more about the history of some of these hybrids, read this conversation between David Sneddon and Jim Lykos, two Australian members of the PBS list. An example of these is xAmarcrinum, a hybrid between Amaryllis and Crinum. See also xAmarygia.
The late Les Hannibal was a longtime breeder of Amaryllis hybrids. Over a period of several decades, he tossed all of the excess seeds from his breeding program into the roughly one acre backyard of his home in Sacramento, California. The result was a sloping hill covered in many thousands of bulbs, scattered everywhere and even leaking into the neighbors' yards. When in bloom it was a remarkable sight, a kind of fairyland of bulbs. Shortly before his death, Mr. Hannibal permitted several people to collect bulbs from his yard. Photos and descriptions of some of those bulbs dug by Michael Mace can be found on Les Hannibal Hybrids 1-25 and Les Hannibal Hybrids 26-48.
Amaryllis hybrids generally range in color from pure white to pink to a mauve color that can look reddish in photos. The examples below give some idea of the range of colors and shapes.
Amaryllis seeds also vary from dark pink to white, as shown by the photo below. They can also be variously veined and mottled. The seed color doesn't necessarily predict the flower color, though -- pink seeds turn darker when exposed to sunlight. Pure white seeds do seem to be associated with white flowers, although we haven't heard of a controlled test of that.
The flowers also vary in size, time of bloom, color patterns on the flower, shape of flower, etc. The photos that follow give some idea of the variety available.
MBQ 01 is an Amaryllis hybrid from Richard Doutt's old Bio Quest International mail order nursery, purchased from him in the early 1990s. It blooms reliably, at the end of summer. It's very vigorous, has a good bud count, strongly radial form, makes offsets regularly, and has large, reasonably dark pink flowers (they start pink and white, and then age to more or less solid pink). Unlike some other dark pink Amaryllis hybrids, these are pure clear magenta, with no mauve overtones. Photos by Michael Mace.
Photo 1 below taken by Doug Westfall is of a selection he received as 'Old Wine #1'. Photos 2-3 by Mary Sue Ittner and Bob Rutemoeller show a couple of the ones received from the dig made by Michael Mace of Les Hannibal's hybrids.
Paul Tyerman offered seed of some of his multiflora hybrids. Below are three pictures of a hot pink one including the bulb with the stem emerging, close up of the flower, and the flower head. The last picture is of a white one with pink tips.