What is a good team to use against high level Venom, Moonstone and Ragnarok?
Mod Edit: Changed title to accurately reflect contents
What level are they? and what is your roster like?
I would at least use someone who puts out an attack/defense/strike tile to negate moonstones purple plus I would attack her first so hopefully she could not use her black.
Silver Surfer, Old Man Wolverine and Jean Grey 
Is this for the ISO-8 Brotherhood PvE? If so, you are probably better off posting in the event thread over at the Events, Tournaments and Missions forum.
OBW, MNMags, CStorm is the team I’ve been using.
2 of those are boosted for the event and OBW steals pink from Venom and denies him using his team stun while providing pink for MNMags to use his pink power which fuels CStorm blue.
moonie is a beast in pve. If you throw out tiles to negate her pink ability, she could still steal tiles with bk ability. She is usually my first target for that reason.
If you do use a tile spammer like Daken, I strongly suggest using a bk user and try to deny bk. Marvel (both versions) is good to use against moonie.
So if you’re in 2* land, I would use daken, wolverine/thor, marvel.
In 3* land, I would use 3* daken, lthor, marvel, or daken, patch, loki.
yeah, without knowing their levels and your roster, its kinda hard to know what advice to give. 2s - obw/ares/third (daken, torch, marvel, storm) are always good. 3 teams abound. I just treat that like a pvp match and if you can fit hood in, it helps: fist/Cyclops/hood is a staple team for me. can also use witch for hood:
thor/cmags/loki
fist/cmags/(cage or panther or Cyclops)
thor/doom/hood
you could always throw 4*s in the mix too, but hard to give blind advice…
What everyone else said… I also specifically pick someone who’s main color (or useful color) is purple, like Scarlet Witch, Daredevil, or Doom. Definitely not Spiderman. You don’t want to drop crap for her to steal. If you use Blade, make sure to wait to drop his punch tiles until after she’s down, or stunned.
I always take out Moonstone first and Rags last. No use making any headway on that idiot while he just heals away. Better to attack the other guy left standing (in this case, Venom).
Denying Purple/Black is key with this trio since Venom also uses those two colors.
Moving this to the Roster Help section, since this appears to be asking for character help..
Side note. It really helps making an online roster, so we can see what you have, and give the best advice we can!!
here are a couple places to make them:
They are level 178 - I have met these three a few times and I just wanted a good team - a 3* great team; I don’t have enough 4* cards to mount an attack.