Pond plants

I've a few pond lilies, some water iris, a red stemmed thing.... but would love some more flowers and also some trailing plants. My pond is above ground, so something that would hand over the sides would be lively. I have lots of the oxygenating plants, water soldiers and some other bits. I dont have fish.but I have loads of water snails... would love something that attracts some dragonflies. Any ideas....