https://extensions.gnome.org/extension/307/dash-to-dock/ Dash to Dock. This extension converts the Gnome Shell dash into a dock that remains visible unless a window encroaches on its space and then it will auto-hide.
https://extensions.gnome.org/extension/2/move-clock/ Move the clock to the left of the system tray.
https://extensions.gnome.org/extension/395/terminal-in-usermenu/. Add a shortcut to the Gnome Terminal in the user menu.
https://extensions.gnome.org/extension/355/status-area-horizontal-spacing/ Reduce the horizontal space between icons in the system tray.
https://extensions.gnome.org/extension/106/remove-user-name/ Remove your username from the top right of the panel; this will save precious space for other extensions.