Yep. Thunderhorn, Skorn, Spirit Harvester, Plasma Storm, Bone Swarm, Thunderbomb, Tempest, Rebuke, Frostburn, Ghost Lightning, Grasp of Agony and Makantor are some (and probably less than half) of the cards which can totally wreck swarm Lilithe. Just tech in some of those and with good positioning you’ll be fine most of the time.
Furor Chakram - How strong is it?
Rule number one of to keep a swarm Abyssian board under control. If you let them have 5 wraithlings on board at 5 Mana, they could easily just kill you with their pre-existing options (double soulshatter pact for 27 damage if everything is range; soulshatter pact + deathfire crescendo for 25 damage if everything is in range). Furor chakram is not really the problem here.
But like everyone has said, there are so many ways to keep that board under control with AoE. Also, you’d be wise to clear their wraithlings with your minions if you’re not already doing that.
difficult to keep it on the board at times when it seems that swarm lilithes have a permanent ritual banishing in their action bar
Most times I find myself having a problem of the rate at which they pump out those wraithlings, since all they need is 4 mana to get 4 wraithlings on the board, or even less. Granted, I see where you are going, but I really have few answers in terms of minions when it comes down to swarm lilithe, since I either play eggmar or drogon magmar, and honestly I don’t feel like pulling a slot out for T-horn, since most of the time they just ritual banish the guy right off the board anyway. Probably thanks to my god-awful mulligans for a while tbh. Whining aside, I do see where you are coming from, probably will invest in more than 2 rebukes now
Despite what some people here said, you shouldn’t use Thunderhorn as your only AOE/Swarm answer unless your Vet and have no other choice. The obvious reason is exactly what you said, Thunderhorn takes a turn before he can do anything, plenty of time to just Lure/Banish it. If your Magmar you should rely on Flash Makantors/Plasmas/Rebukes to deal with Swarm.
Thanks for the suggestion
, do appreciate it, though it really depends on your draws, maybe things just aren’t working out for me 
Dragon Vaath tends to be the hard counter to swarm decks.
You should run plasma/rebuke/makantor and anytime you see Lilith you should Replace hard for those.
Chakram is good, but it’s one of the few good things Abyss for this xpac, and they suffered from heavy needs. They are not in the best spot right now.
If you are playing Magmar, you have so many AoEs that Swarm should not be a problem at all. Consider keeping them during mulligan or wildly replacing for one of them when you don’t find them. It should really be an easy matchup with Plasma Storm, Rebuke, Warbeast and the likes… but any faction can deal with Swarm, there is enough AoEs to kill those small bodies. Swarm Vetruvian is much harder to keep in check
Chakram is absurdly powerful - provided you can get on the board. Against most super-swarmy decks, if you can keep an even footing on the board for the first couple of turns they’ll start running out of gas and then Chakram is a dead draw because there’s nothing for it to boost.
As mentioned, AoE slaughters swarm decks, and dispels kill off the other half of their win cons (deathwatch minions). Tech in an extra couple of those and you’ll be good, speaking as a swarm player that keeps getting rolled by them. >_>
As someone who has played a fair bit of swarm against Magmar, you’ve got quite a few options to clear wraithlings; it’s just a case of putting them in your deck.
You already mentioned rebuke yourself, and a bunch of people said plasma storm/Makantor. You’ve also got diretide frenzy, which gets great value because wraithlings only have one attack, and iridium scale of you don’t want to play minions.
Definitely not meta defining, but it’s a great card. It’s a great way of giving Lilithe some AoE without replacing Soulshatter (if you think Furor is op let’s hope you never get matched against hyperswarm, you’ll change your mind).
Is it strong? Yes. But is it even strong enough to be staple? No. Just balanced 
Soulshatter does the same thing for 2 mana. Double Soulshatter is lethal, not to mention Grimwar or DFC. Try just… killing the Wraithlings my dude, this card is super useless without a board
I do get that, probably will have to run a third plasma storm so I can actually draw it in times of need. Really afraid of dying wish maehv as well, and since plasma storm does jack against their BBS, I normally opt for other board clear options like rebuke. Even though it barely does anything as well. Btw, good luck on the ladder
oh crap, I didn’t think of diretide frenzy, might try that some day
Soulshatter doesnt give minions frenzy, so I’m good with that. The only issue I find is that i can’t get to turn 3 as player 1 fast enough to stop them pulling out that chakram with a board, since everything I play either gets banished or transformed, and I’m left with my lone general. I run 2 Plasma Storms, and 3 Rebukes, but for some reason they hide from me when i need them most.
Maybe it’s the rest of your deck; too many 2 of’s and your deck will seriously start to feel inconsistent in the draw/replace.
As @whyb0t said about the card, it’s nice, but any sense of it in being OP seems a stretch considering soulshatter pact gives the same sudden burst for 2 mana.
Maybe, I really need to stop thinking this is hearthstone and actually put in 3 copies
I didn’t know anyone actually had problems against this card xD Not because I think it’s weak, but mostly because no one has brought it up before. I mostly enjoy this card for the flying minions meme and hadn’t had much success in actual swarming.
I think That chakram is not a good card for swarm deck simply because dfc/soul grimwar are way cheaper, leave a huge minion/general and you can use the other 2 mana for summoning more minions/lure enemies away. On the other hand i think the card could be very good in a aggro deck with flying/rush minions.
The main advatage of furor is that it sticks. I’m currently trying to make furor/firestarter arcanyst deck. Some 3/1 frenzy rush sparks could be fun.
My use for this card has been more geared towards the lovely Revanant. For every hit the frenzy lands, he does 4 damage. That plus the 8 damage to the general is game-ending. Can usually get off 16 damage.