_{Feel free to edit in info on features and/or maintenance.}

There is a blog post at OMG! Ubuntu! that lists five alternatives to gnome-terminal. Another post at Tech Drive-in adds even more other ones. For screenshots, see these websites.

Terminator

"It allows you to split its main window into as many tiles anyone could ever need."

sudo apt-get install terminator

Here are some of its features:

• Arrange terminals in a grid


• Tabs


• Drag and drop to re-order terminals


• Lots of keyboard shortcuts


• Save multiple layouts and profiles via GUI preferences editor


• Simultaneous typing to arbitrary groups of terminals

Tilda

"a configurable “Quake-style” terminal emulator, meaning that it slides down from the top of your desktop when a user-configurable key (default is F1)" _{No longer actively maintained?}

sudo apt-get install tilda 

As said at linuxlibrary: "Tilda does seem to offer more customization options than similar drop-down style terminals":

• Highly customizable interface.


• Set the level of transparency for the main Tilda window.


• Unique built-in color schemes.


• Users are able to reduce the main window to its most minimal state.

Guake

"similar in functionality to Tilda"

sudo apt-get install guake

Stjerm

"comparable to [...] Guake and Tilda. It’s also very lightweight, features tabs, and an option to toggle fullscreen"

sudo apt-get install stjerm

Yakuake

"KDE-native"

sudo apt-get install yakuake

CLI companion

mostly to learn terminal commands

sudo add-apt-repository ppa:clicompanion-devs/clicompanion-nightlies



sudo apt-get update



sudo apt-get install clicompanion

or download a .deb file for it from here.

Eterm

"Eterm is the lightest of them all"

sudo apt-get install eterm

ROXTerm

"Supports features like drag & drop of items into Terminal windows"

sudo apt-get install roxterm

Aterm:

"Extra features include fast pseudo-transparency, optional off-focus fading of text"

sudo apt-get install aterm

Wterm

"An extensive set or runtime options are available resulting in a very customizable terminal emulator" _{No longer actively maintained?}

TermKit

"a command line based system made on top of WebKit"

Terminology

As rajagenupula mentions there is also terminology.

It "can do a lot of things you wouldn't expect from a terminal emulator, like displaying thumbnails for images, videos and documents and furthermore, it also allows you to preview those files directly from Terminology" (quote from webupd8)

Kitty

"The fast, feature-rich, GPU based terminal emulator"

sudo apt-get install kitty

A productive terminal emulator for power users, some of its features:

• split window into panes and navigate between them with the keybaord


• display images inside the terminal


• pick unicode characters like emojis through a visual menu

For a full list, see the kitty website.