Here's an idea: if you're on Linux, use this to sort the list of all paths on your file system (find / -xdev). It's a nice dataset since it's (a) a large list, (b) comparisons are nontrivial, and (c) it's a realistic mix of somewhat-sorted-but-not-completely. (Note: If the file system already sorts everything this won't do the job, so it won't work on e.g. WSL.)