Some of these are races of maize e.g. Chuspillo. Races are large groups
of cultivars grouped based on morphological and ecogeographic data.
Others appear to be Native North American cultivars which are varieties
within a race. Others are modern commercial cultivars, Earliking is an
older sweet corn (1950s) cultivar developed by then Northrup King. I
doubt that it is still available. Likewise Minipop is probably a
commercial name. Others such as Black Mexican and perhaps Black Pop are
almost generic names with many genetically different strains carrying
those names.
Two places you can search are the national Plant germplasm system data
base GRIN at
http://www.ars-grin.gov/npgs/
or the maize database at
http://www.agron.missouri.edu/query.html