The soure is a resistance table by u/dfffgth on Reddit.
Geovishap
Can imbue itself with one of the 4 main elements (Pyro, Hydro, Cro, Electro) in the fight.
Will be stunned for a few seconds if it does a rolling charge into you if you have an active shield, similar to Geovishap Hatchling.
Knocking it out with a shield will give you the achievement "Touch and Go" in the Wonders of the World section.
Resistances
10%
10%
10%
10%
10%
50%
Physical Attack
30%
Corresponding Element
-
Frostarm Lawachurl
Starts the fight with a Cryo armor that reduces over time, enhancing its attacks, as well as becoming more aggressive.
Use Pyro attacks to take out its armor easily.
When in Cryo armor, slam attacks will always create ice spikes in a circle. The dash attack leaves ice mines in its path.
Resistances
10%
10%
10%
70%
10%
10%
Physical Attack
50%
Corresponding Element
-
Fatui Cryo Cicin Mage
Without the bats, she only has 1 attack. The bats can give her a Cryo shield every few seconds, so it's recommended to clear them out to prevent the shield from regenerating.
Creates Cryo spikes in a circle if you get close to her.
Summons ice familiars to help with the fight.
The ice familiars can shoot out Cryo projectiles, home in and deal small explosions, or gives the mage a Cryo shield.
Defeating a Cryo Cicin Mage while all her Cryo Cicins are currently active will give you the "Melting... Away..." achievement in Wonders of the World section.
Resistances
10%
10%
10%
50%
10%
10%
Physical Attack
-20%
Corresponding Element
-
Ruin Grader
Has 3 weak points: Eye, and 2 on the legs.
Weak points are only exposed during/after certain attacks.
Attacking any of its weak points once will stun it for a few seconds.
Attacking the weak points on the legs a second time will render it immobile for much longer. But he can still use laser attacks if you are in front, or behind it.
Attacking the eye a second time will make it unable to use laser abilities.
Paralyze the Ruin Grader's by attacking its weak points will give you the achievement "David and Goliath", in challenger: series III.
Resistances
10%
10%
10%
10%
10%
10%
Physical Attack
70%
Corresponding Element
-
Slimes
Most slimes are considered pure element. This means that elemental damage that corresponds with their element will deal no damage.
Pyro slimes will not take damage from Overload reaction because it's Pyro damage, but Pyro slimes' Pyro element can be extinguished for a short period by using Hydro attacks.
Dendro slimes are immune to all damage if they're hiding underground. Bring them out with Pyro attacks, or face your back towards them to lure them out.
Geo slimes have shield that can be taken out easily using Overload reaction, or Claymore attacks.
Attack with Geo element so you can cause Crystalize reaction and gain a shield to help fight against them.
10%
10%
10%
10%
10%
10%
Physical Attack
10%
Corresponding Element
Immune
Hilichurls
10%
10%
10%
10%
10%
10%
Physical Attack
10%
Corresponding Element
-
Mitachurls
There are variations of Mitachurls using different shields. Their attacks are all the same, but the shields have different properties. After their shield is destroyed, they can make a new one after a while.
Dendro (wood) shield can be burned using Pyro attacks, slowly chipping away its health, but the Mitachurl will try to extinguish it when burned. You can cancel its animation by attacking the shield again.
Geo shield is very sturdiest one. You will need Overload elemental reaction (Pyro + Electro), Claymore attacks, or Geo elemental attacks to help break them faster.
Ice Shield takes increased damage from Pyro attacks, but the shield can heal itself for a certain amount every few seconds.
10%
10%
10%
10%
10%
10%
Physical Attack
30%
Corresponding Element
-
Samachurls
Most of them are easy to take out. You can sometimes stop their casting by getting close to them so they will go for a melee attack.
Hydro Samachurls creates rain that heals the other enemies, so make sure you always take them out first.
Dendro Samachurls creates ivy walls, and cloud poison in an area.
Geo Samachurls will make pillar platforms to lift themselves up, making it harder for you to reach them, and can create spikes below you every few seconds.
Anemo Samachurls creates triple tornadoes, and suctioning vortex in a small area.
Cryo Samachurls have the same ability as Geo Samachurls, except the attacks will be Cryo element.
10%
10%
10%
10%
10%
10%
Physical Attack
10%
Corresponding Element
50%
Lawachurls
Their attacks are empowered when they have their shields up.
Take down their shield easily using Claymore attacks, or Overload elemental reaction.
10%
10%
10%
10%
10%
70%
Physical Attack
50%
Corresponding Element
-
Ruin Guards
Best to use elemental attacks because they have high phys atk resistance.
You can lower its physical resistance using Superconduct (Electro + Cryo).
Ranged characters can shoot its weak point, which is the glowing eye on the front and/or the back, twice to knock them out for a lengthy period of time.
Dodge the missiles easily by getting some distance from them, then move to the sides once they are in the air.
10%
10%
10%
10%
10%
10%
Physical Attack
70%
Corresponding Element
-
Ruin Hunters
You can attack them once they are turned on, even before they start floating.
Its weak point is only exposed once it enters missile mode in the air. Otherwise, shooting the small glowing dot with a ranged character will not do anything.
10%
10%
10%
10%
10%
10%
Physical Attack
50%
Corresponding Element
-
Pyro Flower
Very high resistance against all forms of attack.
You can stun it when it's channeling, by attacking with another element, other than Pyro.
Hydro attacks works the best when it is channeling energy.
Resistances
35%
75%
35%
35%
35%
35%
Physical Attack
35%
Corresponding Element
-
Resistances When It's Stunned
10%
50%
10%
10%
10%
10%
Physical Attack
10%
Corresponding Element
-
Only enters stunned mode when you interrupt its energy channeling ability.
Cryo Flower
Very high resistance against all forms of attack.
You can stun it when it's channeling, by attacking with another element, other than Cryo.
Pyro attacks works the best when it is channeling energy.
Resistances
35%
35%
35%
75%
35%
35%
Physical Attack
35%
Corresponding Element
-
Resistances When It's Stunned
10%
10%
10%
50%
10%
10%
Physical Attack
10%
Corresponding Element
-
Only enters stunned mode when you interrupt its energy channeling ability.
Fatui Skirmishers
Almost all of the Fatui Skirmishers can, and will, use their respective elemental barrier a few seconds into the fight. They massively reduce damage taken while it's up, but you can take them down easily by attacking with an element the barrier is weak to.
You can use a low level character to break their barrier, as long as the element is right.
You can stop them from activating their barriers by constantly staggering, or immobilizing them using abilities.
Hydro Fatui Skirmisher is the healer, so make sure you focus them first.
Anemo boxer's shield will only activate when it is blocking, and you attack it with an element.
Elemental barrier weakness:
Hydro barrier -> Electro
Electro barrier -> Cryo
Cryo barrier -> Pyro
Pyro barrier -> Hydro
Geo barrier -> Claymore/Overload-reaction
Resistances
10%
10%
10%
10%
10%
10%
Physical Attack
-20%
Corresponding Element
-
Fatui Pyro Agents
Inflict an element on them to make them more visible when it goes invisible.
If you are fighting them near an area with water deep enough that you have to swim, you can push them into the water to instantly defeat them.
Defeating a Fatui Pyro agent while they are in stealth mode gives you the achievement "...Till Debt Do Us Part" in Wonders of the World section.
Resistances
10%
50%
10%
10%
10%
10%
Physical Attack
-20%
Corresponding Element
-
Fatui Electro Cicin Mages
Summons multiple electro bats during the fight.
When she starts to channel her ability, she will be enveloped in an Electro shield and chase after you, dealing continuous Electro damage when you she gets close.
You can either get some distance and wait until it's over, or use elemental attacks to cause a reaction and reduce it's shield.