This is a suggestion consisting of effects caused from wearing items part of sets as a costume or as actual armor that in some way effect the player either with stats or as an effect. Any "stat changing" effect is for balancing reasons to make underused/weaker sets to have a reason for use and to nerf the current only over powered set.

Visual/taunt effects.
All of these effects should be able to be disabled in the options as these could obviously make frame rate an issue.
All instances of a effect happening after standing still for too long or typing /afk will replace the sleep effect that normally happens. /sleep still works obviously.
~~~Wolver sets~~~
Skolver set effect: Typing /taunt in chat will cause the player to do a howling animation of them cupping their hands over their mouth before letting out a howl.
Vog Cub set effect: Typing /taunt will cause the player to place a hand on their stomach before letting out a fire ball belch OR placing their thumb under their mouth and blowing fire.
Snarbolax set effect: If the player stands still long enough or types /afk to reduce the time required snarby spikes will begin to circulate the feet of the player around their shadow.
~~~Bomber sets~~~
Bombastic Demo set effect: The player pulls out 3 simple round bombs and begins to juggle. This can be caused by not moving for a set amount of time or typing /afk to shorten said time.
Mad Bomber set effect: When the player dies they let out the same "URRRGG" effect as the BAB but not nearly as loud. Also typing /taunt causes them to pull out a menacing prismatic looking bomb with a super dramatic fuse burning. Right before the bomb goes off they cover the bomb with both hands as the fuse burns out containing the full explosion in their hands. They unclasp their hands letting out the smoke.
Mercurial Demo set effect: Typing /taunt causes the player to pull out a round silver ball. They then place both hands on it and slowly move the hands apart. The ball floats as a electric current flows from both hands through the ball. Then the ball explodes in a static end.
Typing /afk or standing still for a while will cause the player to start playing with lightning in their hands.
Volcanic Demo set effect: Typing /taunt causes the player to pull out a small red bomb and then throw it in the air. It then explodes in a small fire ball.
~~~gunslinger sets~~~
Dead Shot set effect: Typing /afk or standing still will cause the player to pull out a small zombie skull and start to inspect it. It may open its mouth and spit some type of grim on the player. If this happens they throw it behind them out of panic and being to wipe off the goo.
Justifier Jacket: typing /afk or standing still for too long will make the player take the badge off of their hat and start to shine it. Typing /taunt will make the knight turn to the screen and point at the star. A gleam effect will occur on the star and if possible a stupidly smug grin on the knight's face.
Nameless Poncho effect set: The player while using /afk or standing still too long will make them reach into a back pocket and pull out a leather wallet and then inspect their ID. (lel irony I so clever)
Shadowsun set: Typing /taunt makes the knight pull out a small black and pink proto gun. They place it to the side of their head and pull the trigger. This causes many "splash" effects to spawn on the other end of the head to look like black and pink "paint".
~~~Jelly sets~~~
Royal Jelly set effect: going afk from the command or stand still too long makes the player fall asleep..? Nope, they start to fall back and forward and to the side as if they were jelly that was shifting its weight.
Ice Queen set effect: stop moving too long or typing /afk will make the player stiffen and stop swaying. Ice will then form at their feet and slowly climb up them until they are frozen. Moving again will shatter the ice.
~~~Chroma sets~~~
Arcane Salamander set effect: going afk from any cause will make the knight start turning. After about 3 turns arcane (blue) fire forms at their feat and starts to burn a whole in the ground. Once they are to their head in the hole they stop burning and sleep. Moving makes this sink hole slowly fad away after you leave it.
Volcanic Salamander set effect: Fire as you would guess. /Taunt-ing makes them start to well... flow lava from their mouth before turning one of their horns like it is a faucet .
Deadly Virulisk Set effect: The knight will take a deep breath before exhaling a dark purple cloud in the shape of a skull and cross bones after using /taunt.
BRB, GOING TO JUST MAKE A SMALL THREAD TO GET ATTENTION.
TL;DR
A few buffs to make some under rated armor lines more useable and nerf a particular over powered one in a way that still works with what the sets are meant to be or at least seem to be.
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armor "set effects" buff:
The first armor line on the table for buff ideas is the Dead Shot line. Currently it is one of the 4 gunslinger armor lines and one of the 2 that provide shadow defense. Currently it is really only good if you want something good for dealing with undead but really not many people want that. So whats the buff? You may ask.
Deadshot armor buff, "dead shot": This status or buff is given when a player is using both armor pieces in the dead shot line. This buff provides the player with a sort of built in guide that shows them how far the built will travel and how it may change during flight. This "guide" of sorts will provide them with a translucent arrow that goes from the player to the direction of the cursor. The length will be as far as the bullet of the current gun they are using will travel and the width is how wide the built is. What if they are using a pulsar or blitz needle? Good question, the arrow will exspand to be more of a fan for those to show the distance and width of fire. And what about the bouncy wall guns? These ones will be a bit... trickey. If you point it at a wall of monster then the arrow will bounce off to represent the bounce shot produced.
This same effect is provided for the charge attack of the hand guns.
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Next up are the big 3 tank lines. 2 will have a similar if not identical buff with a different name while the other will have something else maybe.

TL;DR
Provide the three major armor tank lines with either a damage immunity or damage shield.

Iornmight plate and Volcanic plate set buff per piece, "Unnoticed dent": any damage under a full pill and a half will be ignored. If you put on another armor piece with the "Unnoticed dent" buff then you will ignore all damage of 3 pills or less. You will not ignore 3 pills worth of damage every time you get hit though. So if you get hit with 4 damage you still take 4 damage, not 1. Yes you can pair a Iornmight Hlem with a Volcanic plate mail and still receive the full buff of 3 damage ignored.
The only thing I am concerned with is the ability to basically walk through spikes (if defense is high enough)and barbs. Maybe a half second cool down of not being hit to avoid aboose or let the walking tanks walk through bramble? I don't know.
Ancient Plate set buff with ALL including shield, "Past Defender's Embrace".
After 20 seconds of taking no damage the player will rescive a temporary health shield of 6 health pills. This means if you take any damage it resets the counter back to 20 seconds. After 20 seconds pass with out taking damage if you HAVE lost any of these "guardian pills" then all 6 will be refilled. These do not count as health, they functions as a defensive. These "guardian pills" should have a hallow center so you can see if you

Nurf "set effects"
I KNOW I KNOW, allot of people don't think the chaos line needs a nerf but I do. So I came up with some set based effects that can function like a nerf.
Keep in mind these are ideas, I just think one of these could work but any combo of these would be fine by me. Pick and chose what you think would be fair.
TL;DR for people concerned but too lazy to read it all.
chaos set debuffs that either are in effect if one or both pieces are on to better force players to be worried about getting hit to better emphasize the glass cannon play style the chaos set is meant to be.
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Chaos set effect debuff "chaotic": If the user has a single part of the armor line equipped they will be given the status "chaotic". Chaotic makes the users weapon switch rate randomized. this will make the player have to cycle through several times to get a specific weapon. Number selection for a weapon will be disabled while using any piece of the chaos line.

Chaos set effect debuff "Unstable": All chaos set armor will have their elemental defense replaced with "unstable" defense. What does "Unstable" defense do? The current defense type changes every time a player gets hit. This means the player could go from shadow/normal, to elemental/normal, to pure normal and finally piercing/normal during a fight. Yes this could save them but more often could put them in risk.

Chaos set effect debuff "Disaster Walker": If the user is using 2 pieces then they will also be given the status "Disaster walker". Disaster Walker causes the player's movement speed to dramatically change when ever they take damage for 1 second. This means if a player using both pieces will have to avoid being hit even more or else they could lose control of them self during a fight. movement speed changes of medium for both increase and decrease have the highest odds fallowed by high, very high, maximum, and then low.

Chaos set effect debuff "Broken Channeling": If the player is hit all weapon buffs will be disabled for 1 second that are provided from armor. This means UVs and level buffs are not effected. This does mean if you had the the cloak on and a kat hood then the buff from the kat hood would also be lost for the second.

Just to mention, I feel the Unstable ,Chaotic, or Broken Channeling debuff should be also put on the black kat hood seeing how it also functions as a glass canon item to keep things even.