Terra is a GTK+3.0 based terminal emulator with useful user interface, it also supports multiple terminals with splitting screen horizontally or vertically.
TTwin 4 Alternatives
TTwin 4 is described as 'TTWin - Windows® terminal emulation is Turbosoft's premier terminal emulation solution for Windows platforms. You can download a free TTWin trial version online' and is a terminal emulator in the development category. There are more than 10 alternatives to TTwin 4 for a variety of platforms, including Linux, Windows, BSD, Mac and GNOME apps. The best TTwin 4 alternative is mRemoteNG, which is both free and Open Source. Other great apps like TTwin 4 are Alacritty, Terminator, GNOME Terminal and foot.