Suitable pond plants for Northeast U.S.?

[jay moussy]

I did remove weeds which were chocking my waterlilies and also the cat-and-nine-tails.
This means I now have more room for other plants, other than the existing irises and waterlilies.

Please suggest easy to care for water plants suitable for the Northeast U.S.

 

[RobAmy]

I am in the northeast and I also have forget me knots, rush, marsh marigold, obedient plants, sweet flag, trollies flower, cardinal flowers to name a few, they all do well in the northeast.