Pymux is a terminal multiplexer and a clone of tmux, but with some improvements, such as autocompletion menu as you can see below.
Panes have titlebar, which shows process command name, window title, also information from like using copy-mode. Using fish-style command-line suggestions, it also has 24-bit color support.
Pymux was created by Jonathan Slenders in 2014, written in Python 2/3 with Pyte, docopt, prompt_toolkit, and wcwidth under the New BSD License (3-clause), currently git-9877c9e (2016-01-09, v0.5 (2016-01-05)), works on Mac OS X and Linux.