Levees, oxbow lakes, and meanders are all features formed by rivers in floodplains.
- Levees are formed as sediment deposits during floods.
- Oxbow lakes are formed when a meander is cut off from the river.
- Meanders are curved bends in a river.
However, glaciers are not formed by rivers in floodplains; they are formed in colder regions and are unrelated to river features.
Thus, the correct answer is (D) Glaciers.