Fighting Cygnar

First of all, i would strongly recommend you start doing list pairings, or that you bring one list that you play against any one that you meet that night. Having to play against a cygnar list specifically tailored against trolls seems like it could be harsh.

A suitable list to have in your pairing to help cover cygnar would probably have a decent ranged presence. Few Troll lists could out shoot a sloan list, but if you have no ranged attacks, you will not have a good time. Casters that stick out as good against cygnar are for example Gunnbjorn (both good shooting and strong anti-shooting), Madrak 3 (spell piercer removes their ARM buffs, and rebuke is super good against stormblades) but basically all our casters can run a list that is suitable against cygnar.

One of our biggest assets is the Kriel Stone. With it, our casters are VERY survivable. Cygnar has tools to remove it though. If an electroleap or arc lightning kills the stone bearer, he can not self sacrifice, and the aura goes away fro a turn. Positioning your models to make it "impossible" to shoot at one model and have the stone bearer be the target the lightning leaps to is sort of a minigame that you and your opponent will be playing. Things like shamans to block LoS to the stone greatly helps with this task.

I think that a PoD list with plenty of shooting is a good place to start. A MK/GK is also very good. There are no silver bullets though, and if your cygnar opponent is a significantly better player than you are, he will (and should) win most of the time. I have found though that chewing through 5 troll heavies is very hard for a cygnar list. Killing one or two is fine for them, but when you have 5 of them, they usually run out of stuff before you do. 5 melee heavies are probably not ideal though in most cases (telekinisis is a pain) but 2 bombers + 3 melee heavies works wonderfully well with many casters.

Thank you for both of these quick replies. As to list pairings I have introduced the idea of doing pairings before but there has been push back against it since the players like to be more 'casual' as they put it. Protecting the stone has been a big challenge for me against Cygnar because of electro leaps. The stone encourages me to put all my stuff closer together but that just makes it easier for Cygnar to bounce lightning all around and against Nemo 3 he killing everything with them. My biggest frustration is how much stuff electr leaps seem to ignore completely.
I am definetely planning to start running Gunnbjorn list soon I just want to get a few more models painted up. This is what I have been thinking of running.
conflictchamber.com/#b71b_-0b020r0resc6fJfJ6R0k

Trollbloods Army - 70 / 75 points
[Theme] The Power of Dhunia

(Gunnbjorn 1) Captain Gunnbjorn [+28]
- Dire Troll Bomber [19]
- Dire Troll Bomber [19]
- Dozer & Smigg [18]
- Mountain King [36]
Northkin Shaman [0(4)]
Northkin Shaman [0(4)]
Troll Whelps [0(4)]
Krielstone Bearer & Stone Scribes (min) [6]

I have 5 points left over for either a solo or the UA for the stone but I'm not sure which would be more important.

I would love to run double Earthborns into that guy. They will frustrate the other player to no end. Half his things can't shoot him and he'll be an absolute bear to hit.

My Calandra def skew list might play well into it.

Calandra
Runebearer
Bomber
Mauler
Earthborn
Earthborn
Axer
Swamp Troll
Janissa
Whelps
Shaman
Shaman
Max Stone w/ UA

Double Earthborns and Swamp troll would be my first line. With their animus' up they will be very difficult to hit and thus e-leap off of (and hopefully you can get them near a lake). If your positioning and Shamans are in good enough place you could even get his ranged pieces into star crossed if they try to shoot anything other than those 3.