They would get bonuses to combat when with a mob/group, much like felar group attacks, but for any groupmates they're with. Attributes to the mob mentality.

Construct - Kind of like a shapeshifter form or druid form, but it's a mechanical construct and takes time to build. Different constructs have different qualities. Defensive construct would be like a defense form, offense, etc. Success of the construction (or the "tier" if you will") would be level, skill, and stat dependant, so you could get different tiered defensive constructs or offensive constructs. This would scale the skill somewhat like shapeshift, and speed of construction could be %skill based. This could be a choice you make at the beginning of the goblin's creation (like a shapefocus) but you can only pick one, and it's perma.

SUICIDE BOMBER. Massive massive damage (to both) with a chance to fail that leaves you dead or at the mercy of your opponent for a long lag time. checks con like a leader when used, has to be prepped before hand. Sort of like the bracers of retribution, but can be detonated when you think you're gonna lose and want to take the sucker with you. Would put you to 0% health (if you're in perfect health, otherwise you'd just die) and three ticks where you'd be incapacitated with a small chance of surviving.

TINKER - tinkering with pieces of armor allows them to be improved or modified. This could have small effects like a 0 tick blind because the goblin put a shard of mirror on his breastplate, small bleeding effect because he put spikes on his armor, reinforced for +ac+hp. Tinkering would be a once only per piece of armor with a dwarf forge like timer and the possibility that your tinkering will do nothing at all and prevent further tinkering. These items would be able to be worn by anyone, so the flag would stay even if it was looted from the goblin. Item would show up like:

<worn on body> a black breastplate (spiked)
<worn on head> a midnight dragon skull (mirrored)
<worn around wrist> a charred leather bracer (reinforced)