There are applications that are extremely customisable to the extent that users can modify almost every single aspect of their behaviour and functioning. iTerm2 is one such application that offers a plethora of customisations from colorscheme, fonts, transparency to keyboard shortcuts. The largest advantage of using iTerm2 is the extensive support for mouse actions. It splits panes easily with CMD+D (vertical) and CMD+Shift+D (horizontally). There is support for keyboard shortcuts and autocomplete suggestions. Packages pretty much everything majority of terminal users would need.