On daily basis we analyze tons of websites to get the best io games on to the list. The position of the game depends solely on likes / dislikes given by users. The more likes the game has the more higher position it gets and vice versa.
Almost every game out of TOP10 best io games has team mode. You simply get special party link that you send to your friends, so that they can join the same server and enable friendly fire. Even if there's no such mode, team members simply add special prefix to nickname to identify teammates.
Hundreds of io games already exist, for every age, gender and interests. You'll find io games for boys and for girls, and of course for adults. Some can be played in 5 minutes during coffee break, others may require hours to upgrade and get higher rank. Various categories: shooters, strategies, racing games and many others. Best is games list will guide you in the world of .io games!