Alan, I could name a few hundred varieties of corn with su of which Golden Bantam is an example. I’ve grown about 50 such over the years including Luther Hill, Whipple White, Buhl, and others that I sold to Sandhill Preservation for seed. Varieties with se+ are much more limited as it is a gene found after 1950 therefore was widely used in hybrids such as Kandy Korn which was available in the 1970’s. The original variety where se was found was Narrow Leaf Evergreen. One of the complications with se is that for many years it was thought to be on chromsome 4 along with su. Better analysis about 30 years ago finally determined it is on chromosome 2 therefore can be readily combined with other genes for enhanced sweetness. This is the source of the “synergistic” and “augmented” varieties commonly sold today. Synergistic combines sh2 + su + se in varying combinations so that each ear has a few kernels of each type. The usual mix is to stack sh2 and se on top of su such that 50% of kernels are su, 25% are sh2, and 25% are se. Augmented is homozygous for sh2 with se and su stacked on top such that 100% are sh2 with varying percentages of kernels on the same ear having se and su. The reason for stacking these genes is to enhance texture and flavor while boosting overall sweetness.
One problem with sweet corn is that there are very few really good open pollinated varieties. By this, I mean that combining large ears with excellent sweetness and good flavor in an OP line is very rare.
One item of trivia to know about sweet corn is that it is derived from flint corn. A single gene mutation turns flint corn into sugary corn like Golden Bantam. If you combine sugary with ordinary dent corn, too much starch is retained in the kernel resulting in odd textures and flavors.