sudo apt update
sudo apt install gnome-tweaks gnome-tweak-tool
The following are some useful Gnome Shell Extensions that come with Ubuntu 18.04.
If your computer or laptop do not has hard disk led, this extension is good for you.
sudo apt install gnome-shell-extension-hard-disk-led
If you do not have multi-media keyboard, this extension is for you.
sudo apt install gnome-shell-extension-mediaplayer
You can monitor the CPU loading, Memory usage and Internet traffic with this extension.
sudo apt install gnome-shell-extension-system-monitor
You can know current and forecast of your local weather with this extension.
sudo apt install gnome-shell-extension-weather
If you have some old system tray icons, you may need this extension. However, some old system tray icons do not compatible with this extension.
sudo apt install gnome-shell-extension-top-icons-plus
Run Gnome Tweaks to enable the extension(s) that you have installed. After that, logout and re-login.
To see all the Gnome Shell Extensions that come with Ubuntu 18.04.
apt-cache search gnome-shell-extension
That's all! See you.