This trope is under discussion in the Trope Repair Shop.
Tony: We'll lose.
Steve: Then we'll do that together, too.
A group of people who work together, whose members are split along particular roles based on complementary skills and personality traits that contribute to group dynamics in their own unique way. Many of the most common team roles are listed under The Index Team. The Team may or may not have an actual name of its own.
Most importantly, the Team has to have teamwork and Team Spirit as its basic modus operandi; that is, they would seek to tackle any problems that any of their group encounters together, unless circumstances dictate otherwise (e.g. one of them has been ambushed while away from the others, or the problem involves participating in an official competition of one-on-one matches).
The roles may loosely be seen through the lens of the classic Five-Man Band (lead, foil lieutenant, powerful, technical, emotional) but without strict numerical or gender restrictions. Other non standard Party Members are also fair game as long as they are actually a group that works together, and the roles relate directly to group dynamics-not just a listing of a series' cast members.
Further there may be two or more characters holding the same "archetype", though often in different ways; a team may have both a scientific tech-savvy The Smart Guy and tactical manipulation-savvy The Smart Guy. Likewise, you may have two Big Guys, one being a long-range heavy-weapons specialist, and the other being a Big Freaking Sword-wielding close-quarters bruiser.
This is the Super-Trope to Power Trio, Five-Man Band and The Magnificent Seven Samurai. If it's a military group, it's either The Squad or a Command Roster. If enough members are legitimately badass, it may also be a Badass Crew. For professional wrestling examples, see Power Stable. They can also be a Dream Team. Compare and contrast Band of Brothers and True Companions. See also Cast Calculus for typical breakdowns.
See Establishing Team Shot for when the team is introduced together.