Using SQL and being able to think both relationally and non-relationally are a valuable skill.

Working with text based datasets is a skill I don't see enough of even though it is quite prevalent. (I have spent more time than I've wanted using tools like Monarch to make text databases relational through an automated workflow)

The reality of development is working with an existing, or multiple datasets homogeneously. Cool use of the JOIN command, a title like "Join text files using the command line" probably would receive a positive response here.

It'd be sweet if everything was a nice and clean API data call with a bow on it, but part of being a developer is enabling that where it need to be.