Mangroves are about the only ones that are technically plants I think, but there are certainly a variety of macroalgaes that can be used in some tanks.
They don't tend to be very popular in reef tanks (although very popular in sumps/refugiums for reef tanks) because they tend to take over and spread everywhere, but in fish only tanks, they certainly add impact and movement to the display.
I would love to set up a seagrass tank, but it is difficult to get hold of in the uk.