Thanks for the help @MikeMcQuaid . I tried that, but it just returns:
Error: No available formula with the name "pdfjam"
==> Searching for a previously deleted formula...
Error: No previously deleted formula found.
After digging some more, it looks like pdfjam is included as part of mactex. That solves my immediate issue, but I'm curious as to how I could have tracked this down vs luckily noticing it.