Mono-class parties are boring mechanically, at least in other games, but thematically very interesting. A party of all Wizards at Wizard Academy, or a party of all Fighters on the front line of a war, or a party of all Clerics on a missionary expedition gone sideways. Or all Sorcerers fleeing the law, or all Barbarians here to kick ass and chew the skulls of their foe, or all Butchers here to facilitate aforementioned skull-chewing...
More to the point, team abilities let the players decide how they want to solve challenges. If they want to socialize with everything in the dungeon, all Jacks. If they want to sneak past everyone and never enter combat, all Thieves. If they want to explore everywhere in the game world, all Rangers. If they want to skip all the planning and exploring and get right to Plot and Battles, all Paladins. And so forth.
|the quintessential all fighter party.|
Fighters: Your initiative chits can be spent to give any party member a turn, so long as that character hasn't gone yet this round.
Thieves: Use the party's highest, not lowest, roll for Stealth.
Clerics: If you all follow the same god, you collectively get two free miracle dice that you can use to power miracles without risk of Disfavor.
Wizards: You can bleed Flux onto other Wizards in the party when you cast spells, giving them the Flux instead of you.
Adepts: You can make Combo Attacks as Stunts. Apply all the fighting styles of adjacent characters to a single attack, and step up the damage die for each contributing character.
Barbarians: Whenever you Rage, you can automatically activate the Conduit Doubles effect of the first rage die you rolled for the rage.
Butchers: You can collectively prepare a Feast during a daily rest from your rations, which gives everyone in the party the effect of a single Cut for the next day.
Engineers: If at least two of you collaborate on using Dungeon Architect, you can make modifications in a combat turn that then fall apart afterwards.
Jacks: You can pool contact dice and use them to upgrade each others' contacts, and Trustworthy Face applies to everyone in the party, including your hirelings and other NPCs travelling with you.
Rangers: Double overland speed and consume half rations. You can't get lost except by magical interference.
Paladins: Your collective piety never leads you astray. You can always force a fair fight (if you yourselves are fighting fairly), and know the general direction to your objective.
Sorcerers: You can breed the spells in your heads together during daily rests. Instead of generating fully random spells, get spells hybridized between yours and your partymates', as Spellchemist.