I’ve been using iTerm2 for 2 or 3 years now, and I’ve only just now noticed the ‘toolbelt’ option in the window menu. You can also hit ⌘⇧B to bring up the toolbelt.
The toolbelt expands to the left of the terminal window and allows you to quickly and easily show all running jobs and send standard signals to the process. You can also switch between profiles (something I rarely ever do), access clipboard history and save textual notes.
Here’s a short video demonstrating the feature: