Usually Interval Trees, RB Trees, B Tries, Heaps, Bitmaps etc are used to store data.
Generic Cache for multiple modules where complete file data is not available at same time. File is stored in extents. Interval trees, Extent trees and B trees can be used. Here data may be stored in the disk but how to access data (metadata) is stored in data structure.
Read Ahead Buffers: To speed up applications performance a predictive algorithm uses pattern to read data before requested. In this case also extents can be used.
Images might be stored in bitmap with other ds to keep a count of redundant information.
Most use cases are related to high Disk IO latency and data redundancy elimination.