OK, Here goes,
Using Tom Penfield's "Directory of Buried or Sunken Treasures and Lost Mines of the United States 1971," I have found a ton of neat stuff for you. Some is dry and some is wet. Now, these are just listings. You will have to research the full stories yourself:
1. Galleon...Mixed Treasure...$1m...Useppa Island....Lee County
2. Gasparilla's Flagship...Gold Bars...$11m...Bell Bar...Lee County
3. Chief Carlos...Mixed Treasure...$100m...San Carlos...Lee County
4. Matt Mckay...Gold Coins...$50K...Fort Meyers...Lee County
5. American Frigate...Gold Bars...$10M...Gasparilla Island...Charlotte County
6. Jose Gasparilla...Mixed Treasure...$30M...Gasparilla Island...Charlotte County
7.Galleon...Mixed Treasure...$

...Naples...Collier County
8. Gasparilla Cave Treasure...$

...Tampa...Hillsborogh County
9. Many Galleons...$Billions...Mixed Treasure...All the Keys...Monroe County
10. Off of Sanibel Island there are supposed to be 12 chests of treasure that were buried on dry land. Eventually, the land sank, and every once in a while after a good storm, the chests are visible for a short time in the water.
Good Luck-Mike