I have noticed in the past four or five years there are less choices of annuals. First, it was the snapdragons. I can hardly find snaps in the big box stores. The only ones that are offered are the little, short, pixie ones. I have been able to catch a few at a mom and pop nursery, but they closed up shop this year. :( For the last couple of years, I have tried to grow my tall snapdragons from seed which for me, is really a hit and miss project. "Sometimes" my snaps re-seed, but I hate to take the chance and not have any. They are one of my favorite annuals.
The last two years, I have had trouble finding the plain, but fragrant and pretty dark purple petunias. They have lots of the light purples and pinks but not the dark purples. The dark purples are more fragrant.
And forget about finding something like Angelonia, Heiloptrope, Torenia and other less known annuals.