Online and unblocked games are those that can be played without having to download them from the internet or buy them from a store. They are usually browser-based games, meaning that they can be played directly in the web browser without having to install any additional software. These games typically do not require any registration or login details, making them suitable for people of all ages. Popular online and unblocked games include strategy games, card games, puzzle games, and action games. Some of the most popular online and unblocked games include Agar.io, Slither.io, and Tetris.