Goblin Janitor

This as inspired by a game of reverse DnD where player where playing monster vs human

Room maintenance

Goblin Janitor are just good to maintain traps and treasures. They do this with out thinking.
Has part of a short rest you can re-arm trap and clean in a number a room equal to your profiency bonus

Dungeons attunment

Starting at lv 3 when ever you trigger a trap you can use your reaction to decide to not to or redirect the trap to affect a square 5ft from where the trap is suppose to affect. If you use this option you can add your sneak attack damage to the trap damage. (This does not count toward maximum time you can use Sneak attack in a round)
Starting at lv 10 when you use your reaction you can also add your profiency to the DC of the trap
Starting at lv 17 When you use this ability the trap also has a chance to stun the target for 1 round if they fail the initial saving throw from the trap

Quick count

Starting at lv9 you can do investigation (int) has a bonus action to loot a body. you also have advantage to investigation (int) roll. And you know ho much gold there is in a container. You automaticaly find bag of holding and portable hole. You can also acces stuff in those magical container with a bonus action

Team Manager

Not alot of Goblin make it at that level. for sure you have attain the level of manager. Starting at lv 13 anyone that is in your crews and is with in 15 ft of you is consider to have +1 to profiency maximum of +5 to profiency bonus for Save/Skill check.  This bonus can not be stack. At lv 17 The bonus to profiency also apply to spell save and attack roll

Trap master Strategist

You are cunning enought to make people fall into the trap. When you deal Sneak attack damage you can also move the target 5ft toward a trap. there is no limit to the number of time per round that you can do this. (so you can also move people that tigger trap with your reaction)