I use a lot of programs from Plan9port, including rc as my shell. rc has no history file support.

Instead of relying on my shell to create my history, I use my text editor, acme. Acme has this neat feature where you can spawn a shell within an acme window, which means that it's essentially a terminal inside of a plaintext file. At any point it can be edited or saved. So that instead of having a history file, I have a history directory.

Whenever I do something somewhat complex or I figure out the perfect awk script to preform some function, I save all the relevant commands with their output to a file in my history directory. For example, I have a file for generating new git repos for stagit on my server. I find it a much better reference than a simple history file, because not only do I get the command(s) that worked, I also get why they worked, and why another command didn't. I can even add notes while I'm executing the commands, or after I save the file. It gives me a better understanding of my command history. I also don't have to sift through a million 'cd' or 'ls' commands.

If I had a proper history file, my top ten would probably be some combination of p (alias for plumb), ls, cd, git, man, rm, B, mv, Sel (used for looking through my music library in acme), and ssh.