Water lake

Water lake was a small area that contain water. It generated in every biome except desert and desert hills.

Description
Water lakes, which were small pools of water source blocks, could generate above sea level or inside caverns. They could also generate isolated underground, connected to no other structures whatsoever. When in a snowy biome, these small lakes are never initially frozen but turn to ice if exposed.

Water lakes generated with a small air pocket above them, which might result in floating sand, floating snow cover or even floating trees above the lake.

Generation
Water lakes were most common, generating in almost all Overworld biomes excluding the desert and desert hills biome In Java Edition, the air pockets above water lakes were generated with cave air instead of normal air. This was true even for lakes that are exposed to the open sky.

Dungeons were able to generate attached to water lakes.