The Swampland Expansion

Swamps are the most boring and gloomy place in Minecraft, which hasn't become more popular due to Frogs or Mangrove blocks. You'll have to do it yourself: try the The Swampland Expansion mod to add new mobs and blocks to swamp locations. Features include: Mangrove Zombie (hostile, health 25, slowness effect), Ancient Swamp Zombie (hostile, health 22, hunger effect), Swamp Drowned (hostile, health 22), Swamp Crab (neutral, health 11), Swamp Fish (neutral, health 10), Swamp Spider (hostile, health 22, poison effect), Red Frog (neutral, health 10), Poisonous Frog (hostile, health 11, poison effect), Swamp Merchant (neutral, health 20), and Swamp Grass (hostile, health 25, slowness effect).