Parodied: The Five-Man Band named Five Man Band recieve equipments or powers that require a sixth member. So they hire Senso Ranger, a temporary worker whose job is to help the team.
Deconstructed: Herman outshines Team Bob in every way, provoking the Green-Eyed Monster in them to seriously contemplate murdering him.
The team is not happy that they went through so much pain and suffering and then this guy shows acting better than them.
The rest of the team is motivated to work harder, so their skills can be put to use cooperatively.
Zig Zagged: Herman is a part time team member who comes and goes, depending on the circumstances.
Alternatively, he starts out as a sixth ranger traitor, but then moves to the side of good. He is then reminded of his debt which he must pay the dark side. He also becomes emotionally attached to Alice, she then finds out. He does not want to cause shame to his country, but now Alice is pregnant, creating a Soap Opera-style father plotline.
The additional party members are all Guest Star Party Members and don't actually join the party, because it's full. Instead, they give the party effects, e.g. Instant Healing, HP+10 etc. However, they all have triggers, and their skills must all be attached in the skill slots, but since they can only be on one party member, they'll take the trigger. For example, Herman's song is triggered when all party members reach Critical Condition to raise all their stats, and if you put Kitty's Magisplosion in one of Bob's Skill Slots, Magisplosion will consume all of Bob's Mana to KO an opponent as a Last Ditch Move when Bob's almost KO'd by magic.
Averted: Herman leaves the team as soon as his intro arc is done.
Enforced: "We need a new guy! Someone to shake things up, and more importantly, provide a boost in sales!"
Lampshaded: "Good thing we added you to the team. What would we ever do without you?"
Invoked: Bob puts an ad out in the paper for a new guy.
Defied: Herman refuses to join the team and leaves immediately after he's introduced.
Discussed: "I think it's about time we brought in a new guy. What do you say?"
Conversed: "The bad guys are beating the good guys hitting all their weak points and dodging their best attacks! Their only chance would be someone with a different set of skills and powers, like the completely unrelated guy they introduced five minutes ago... and here he is!"