Among the Super Smash Bros. community, it is common for distinguished groups (such as the Smashboards Back Room) to create Tier lists, rankings of a character's potential in tournaments. The Smashboards tier list is generally seen as the "official" tier list, though many other groups have created their own. The lower the number on the tier list, the greater the potential for that character to do well in tournaments.
SSB tier list
SSBM tier list
SSBB tier list
Controversy over tier lists and their existence
The overwhelming majority of the Smash community believe that tiers exist and not all characters in each game are perfectly balanced. However, there are many casual players in the Smash Bros. community who disagree with the idea of tier lists. It is a common misconception among these players that all characters in the series are relatively balanced in ability. Such people are known as "anti-tierists". However, it is extremely difficult to perfectly balance a cast as diverse as that in Super Smash Bros. Furthermore, several prominent members of the community, such as Mew2King, have performed exhaustive tests on the objective qualities of certain attacks, such as speed, hitbox duration, priority etcetera. Some characters are objectively more favorably endowed with these qualities than others, providing strong evidence to base tier listings. All in all, some characters simply have obviously more potential than others. Tournament results have shown that some characters are more viable than others; the winners of Melee tournaments most commonly use Fox, Falco, Sheik, and/or Marth, and the winners of Brawl tournaments most commonly use Meta Knight, Snake, Diddy Kong, Ice Climbers, Falco, and/or Olimar. Even low-tier characters have tournament representation and their dedicated mains, such as Gimpyfish, Taj, and Vermanubis. These players routinely place lower than top and high tier mains, despite putting in a similar amount of dedication to their characters. Additionally, the anti-tiers' arguments are constantly refuted, and they have failed to come up with new arguments that disprove the existence of tiers.
Tier lists have been frowned upon by people outside the Smash Bros. scene as well as they see tier lists as restrictions on who will be played in tournaments. The tier list does not restrict the characters played, because the tier list ranks characters based on their potential in tournaments, not who is the "best" character to play. Some also believe that it limits the ability to learn from mistakes caused by players as the failure would be pinpointed on their character that they use rather than the player's own ability. However, any competitive player who mained a character would know their character's weaknesses and strengths, and a player would be able to tell when a mistake was their own fault or due to a weakness of their character.