I've been thinking all day about bringing special abilities back into the highly streamlined Danger Patrol Pocket, but since I played it as "Dungeon Patrol" in Eberron's setting, I used different skills, matching Powerful, Deft, Mental or Magical with Battle, Stealth, Influence, or Exploit...
Here are my initial thoughts:
Fighter - Weapon and Armor Proficiency - +1 hit when using Weapon d8, -1 danger when using Armor d8
Rogue - Swashbuckling - If you fail to take out a threat, you can split the resultant bonus dice between two threats, instead of only placing them on one.
Ranger - Favored Enemy - Once per scene, you can choose one enemy threat and give it a weakness to Deft Battle moves.
Cleric - Divine Protection/Healing - Once per scene you can choose to either remove all of a character's current threat dice or remove a complication from the scene without taking an action.
Mage - Practiced Spell - Spend a Mage Spell d8 after your roll to give +1 hit to the roll.
Paladin - Smite - Ignore a threat's strength when using your Holy Weapon d8.
Druid - Shape Shift - Once per scene, swap the rating of one of your Styles with the rating of one of your Moves.
Elf - Enchanted Skills - Choose one of your Elf d8s. That d8 is now a d10 (rolls of 3 or less with it do not generate danger results).
Dwarf - Stout and Gruff - When you take threat dice (d4s) from danger results, one of the dice is a d6 instead.
Human - Adaptable - You have one additional bonus d8 (total 3) for your Human bonus dice.
Gnome - Illusions - When using Influence moves, you can choose before the roll to inflict +1 hit by taking +1 threat dice after the roll.
Dragonborn - Dragon's Breath - Once per scene, re-roll any Powerful Battle danger dice after your roll. The second roll counts.
Changeling - New Faces - When attempting Deft or Mental Influence moves, choose before you roll: do +1 hit or -1 danger.
Warforged - Metal Man - If you would be taken out, you can spend a any of your bonus die to reduce the danger by 1.
I have no idea about their balance, but these seem suitably "low-impact" while still providing a character with two unique abilities that no one else has. I would love feedback, but I mainly just wanted to put it out there for anyone else looking for ideas.