You know how five-man bands are usually reserved for super robot anime, where they are given vehicles that combine to form a larger robot? Say that you applied a five-man band in a real robot anime, where mecha cannot combine with each other. How would their mecha fight without the ability to combine?
For me, it's the following:
1. The Leader: Either a well-balanced unit or a melee unit.
2. The Lancer: Either a marksman if the Leader is a melee fighter, or a melee fighter if said Leader is well-balanced.
3. The Big Guy: The heavy-assault unit.
4. The Smart Guy: Either a scout if the Lancer is a marksman, or a marksman if said Lancer specializes in melee.
5. The Chick: Either an engineer or radar specialist.
Majestic Prince is one example of how to do a five-man band in a real robot setting, rather than a super robot one, as were Gundam Wing and Gundam 00 (and yes, in the case of the latter, I'm including Sumeragi Lee Noriega as the Chick in Celestial Being, due to her being the tactical forecaster of the group). I'm sure that there are other examples I've missed.