deheader analyzes C and C++ files to determine which header inclusions can be removed while still allowing them to compile. This may result in substantial improvements in compilation time, especially on large C++ projects. It also sometimes exposes dependencies and cohesions of which developers were unaware.
Dateutils are a bunch of tools that revolve around fiddling with dates and times in the command line, with a strong focus on use cases that arise when dealing with large amounts of financial data. Their target market is shell scripts that need date calculations or calendar conversions, and as such they are highly pipe-able and modeled after their well-known cousins (e.g. dtest vs. test, or dgrep vs. grep).