Clan Name: Anonymous
Clan Bio: You see them every day, yet you never really notice them. The homeless man on the corner begging for change, the window washer across the street from your office, the old Lady sitting next to you on the subway. They look like every other regular citizen in Clint City, but their quiet and unassuming facade conceals a secretive clan which uses their anonymity to their benefit. By the time you realise who they are, it's already too late.
Clan Theme: Ordinary people that operate in perfect cohesion, working towards their leader's sinister goals.
Clan Bonus: Protection - Power and Damage

A clan of Government officials, good and bad! - easy to make since they can be connected to both Uppers and Montana
A clan of zombies and different types! - difficult but possible since drugs created Berzerk and some characters have back story regarding them (Milena), not to mention the Nightmare clan
A clan of ethnic people - can be related to Ulu Watu
A clan of people from the past - opposite of Vortex

How about:
The Elders

The old people of Clint city have woken up from their retirements after being completely irritated by the fighting and noises. Their motto is Mind over Body , Experience over Agility .
Discovering a new Elixir that allows them to use their bodies to the max , they are scary as sh1t!
Anyways , watch these people stick together and fear the power of their rambling about their past .
Oh yea, their Leader will be Gandalf

Bonus: Support:-4 Opponent attack Min 4

Elders have been tossed around for a while now, but they're kinda the same as robots. Already spread across several clans and wold seem redundant to have one just for them. Plus that bonus is bit over overpowered when compared to Rescue and Montana.
Likewise, zombies would be pretty redundant since Nightmare has them, Nightmare has means of creating them, Skeelz have means of creating them... You get the picure.

What if the robots were not made of metal? Say they were rock (or clay)-based, like Golems.
Bonus: Focus: +1 Power
Gains 1 Power for each passing round, so there's no effect on the first round, but the second has +1P, the third is +2P, and the final is +3P. Slow and steady. Would work well with clans that like to hit first, like Freaks.

Counterpart Bonus idea: Haste: +4 Attack
Starts with +12 Attack in the first round, round 2 has +8A, round 3 is +4A, and no effect in the last round. Hit hard and fast.

Pareside (Parasite + Reside)
A clan of insectic creatures that have a nasty habit of merging with random objects (Cars, Stop Signs, Frozn's Ice-guns, etc) and are extremely territorial. There's plenty of inspiration for bug-monsters and anti-bug specialists for other clans (La Junta, Sakrohm, GHEIST) for combating them.

I love the bonus idea of copy opp ability. people will be unhappy, I realize that, but it becomes more based on whom do you play which cards against. so like against Kolos, a 7/6 card with SOB ability will be a KO (problem I know). or a strike back activated ability. (played 2nd in the round)