There are many alternatives to RightToClick for Firefox and since it's discontinued a lot of people are looking for a replacement. The best Firefox alternative is NoScript, which is both free and Open Source. If that doesn't suit you, our users have ranked six alternatives to RightToClick and four of them are available for Firefox so hopefully you can find a suitable replacement. Other interesting Firefox alternatives to RightToClick are Ghostery (Freemium), ScriptSafe (Free, Open Source) and Enable Right Click and Copy (Free).
Ghostery sees the invisible web - tags, web bugs, pixels and beacons. Ghostery tracks the trackers and gives you a roll-call of the ad networks, behavioral data providers, web publishers, and other companies interested in your activity.