Pistia stratiotes is the usual 'water lettuce' found in pond shops around here that is a massive invader in warmer regions, along with those water hyacinths. I've used both around a large outdoor pond to give wee frogs a place to go out in the water, I don't really like the look of them as they appear too exotic a platform to take pictures of my native frogs on.

The Amazon Frogbit you mentioned does look like little lily pads, so that might be nicer. The pond also has some slowly multiplying nativish lily pads of some sort, but I'd like more water foliage but I'd also like them to die off in the winter if they're rampant multipliers

The Salvinia natans does very well outside in the summer, and survived indoors until my goldfish predictably trashed them.