Anniversaries and birthdays, Halloween, Thanksgiving, Christmas and Fourth of July.
For us Thanksgiving and Christmas aren't super important because we're not religious but we use them as times to get together with family and friends and eat good food while chatting. We do decorate for Christmas but it's mostly for the little guy.
Also there is Mardi Gras which I consider a holiday but I don't celebrate it anyways. Not so much around here but Cinco de Mayo is a big holiday in some places.
Sweetest day is kind of like Valentines day, just a day to get your lady jewelry, I live in WI, I don't know how many states celebrate Sweetest day, but we as a state celebrate it but we as a couple don't celebrate it. I don't see any reason to make him shell out MORE money on me lol.