The ProxyBar extension allows you to change the proxy server through the sidebar. This extension also allows you to save the required proxy servers. And so you can switch between them quickly.

ProxyBar - Easily Change Proxy Servers in Firefox
ProxyBar is a Firefox add-on that enables users to change proxy servers easily. It provides a sidebar interface to quickly set up and switch between saved proxy servers.
Add-on stats
Full description: See detailed description
Source: Firefox Browser Add-ons
Add-on safety
Risk impact
ProxyBar requires very minimum permissions.
Risk impact analysis details
- High Allows reading and modifying clipboard content, which can be sensitive, posing a moderate privacy risk.
- Low ******* ****** ** *** ********* ********
Risk likelihood
ProxyBar has earned a fairly good reputation and likely can be trusted.
Risk likelihood analysis details
- High This extension has low user count. Unpopular extensions may not be stable or safe.
- Low **** ********* *** ******* **** **** * ****** **** ***** ******** *** **** ****** ** ** ****** *** *****
- Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
Upgrade to see full risk analysis details
Similar add-ons
Here are some Firefox add-ons that are similar to ProxyBar: