Wow, that's a really open ended question....There are so many plants that can be planted in the spring....TONS, and TONS of them!
A lot depends on what zone you are in.....certains plants will only grow throughout certain zones.
Then you have your annuals that just grow one season. And your perennials that will come back for 3-4 or more years. Then you have your bulbs too.
Then you have to take into account what kind of sunlight the area you want to plant in gets. Some flowers like full sun, some shade....some part sun/shade.
Glad to see you back though!
You might want to post a question with a few more details down in the plants/flowers section!
So how have you been doing?