Ideas for my Swamp Themed Mod (no entities)

I'm developing a marsh biomes mod, the mod is already posted but I'm out of ideas, my mod already has mangrove, cypress and bayou biomes, mud and its bricks, fireflies, a new "swamp tower" structure, New flowers of 6 colors called bromeliads, celendula flower, roots and other not so important things, so if you have an idea, help me.