I will explain briefly which Google Chrome Extensions I use to optimize my (and your) web browsing experience.
These extensions should work on all Chromium based browsers including Opera.

AdBlock Plus

Blocks most of the advertisment on sites

Google Data Saver

For slow connections or days when you are downloading much and want to keep your network usage low

Flash Control

Disabled Adobe Flash objects, but re-enable them by clicking on them. Saves CPU and memory usage

Ghostery

Blocks spyware and social media addins. Security improvement

HTTPS Everywhere

Tried to use HTTPS. Security improvement