It's perfectly natural, so many systems follow Pareto. From Wikipedia:
- The sizes of human settlements (few cities, many hamlets/villages)
- File size distribution of Internet traffic which uses the TCP protocol (many smaller files, few larger ones)
- Hard disk drive error rates
- Clusters of Bose–Einstein condensate near absolute zero
- The values of oil reserves in oil fields (a few large fields, many small fields)
- The length distribution in jobs assigned supercomputers (a few large ones, many small ones)
- The standardized price returns on individual stocks
- Sizes of sand particles
- The size of meteorites
- Severity of large casualty losses for certain lines of business such as general liability, commercial auto, and workers compensation.
- Amount of time a user on steam will spend playing different games. (Some games get played a lot, but most get played almost never.)
I will also add popularity of words in a language, and, the most popular instance: individual wealth distribution.