Plants:
* Aquatic plants: Water lilies, cattails, reeds, pondweed, water hyacinth, algae (both visible and microscopic)
* Emergent plants: Cattails, reeds, bulrushes, sedges
Animals:
* Fish: Carp, bass, catfish, sunfish, trout (depending on the region and pond size)
* Amphibians: Frogs, toads, salamanders
* Reptiles: Turtles, snakes (water snakes)
* Insects: Dragonflies, damselflies, water beetles, water striders, mosquito larvae, mayflies
* Birds: Ducks, geese, herons, kingfishers, grebes
* Mammals: Beavers, muskrats, otters (depending on the region and pond size)
* Invertebrates: Snails, clams, crayfish, worms
Other things:
* Rocks and sediment
* Debris: Sticks, leaves, fallen branches
* Water: Depending on the pond, the water can be fresh, brackish, or even slightly salty
Things that might be in a pond, but you wouldn't want to find:
* Pollution: Runoff from nearby farms, industries, or streets can contaminate a pond.
* Invasive species: Some introduced plants and animals can damage the natural ecosystem.
Remember, the specific organisms you find in a pond depend on its location, climate, and other factors.