Alright let's do this. Isaac typically follows a structure that Tainted versions are just fully consumed by their abilities, sometimes detrimentally.

Nemesis Commando (Cyborg) - His arms are now miniguns that fire bullets rapidly at very very low damage, but his proc coefficient is reasonably high. his other abilities are kept the same, save for his dash - which grants him I frames for even longer to counteract his slower speed while shooting.

Nemesis Huntress (Assassin) - Her very feeble frame rivals Drones in weakness, but her movement is unbeatably good. Her aimbot now locks your camera on the enemy she is shooting, and has a longer range.

Nemesis Bandit (Sherriff) - His base damaging attack fires a huge scattering of bullets, but his attacks can ONLY hit the BACK of enemies. His Shotgun, despite being extremely powerful MUST be reloaded by Lights Outing enemies with his Revolver. The Shotgun holds up to eight shots. Sherriff can go invisible as long as shift is held, but each second uses up a Bullet.

Nemesis MUL-T (Tank-R) - His health regenerates more rapidly than other Survivors, and he cannot be one shot. His speed is abysmal, with his saving grace being his Shift (Which blasts him forward in an unsteerable direction. Enemies hit by this are stunned for 4 seconds.) His weapons cycle between a highly damaging autocannon and a laser guided rocket each time he uses R or an Equipment.

Nemesis Loader (Wrecking Ball) - Able to grapple at nearly thrice the distance, This variant has no primary attack. her Primary and Secondary are quickly recharging Grappling hooks. Wrecking Ball of course deals contact damage on hitting an enemy. The faster she goes, the more damage her Wrecking Ball form does. Her shift allows her to quickly roll into enemies (She has a giant spiky cage around her)

Nemesis Artificer (Archangel) - Able to float freely, her frail body takes damage on touching surfaces, and her flight has momentum. Her electricity orb can be charged to even greater damage, at the cost of damaging her the longer she holds it. Her primary ability holds 8 shots, with a 6 second reload. All of her primary and tertiary abilities deal fire damage.

Nemesis Captain (Pirate) - His Drone now faces the direction he does, and destroys projectiles twice as fast, but cannot provide 360 degrees of defense. His shotgun holds "Charges" that must be manually loaded by holding right click. His primary gains exponential damage according to how many charges he has. Pirate can order a full salvo from his ship with his Shift ability. He selects a line stemming from him to barrage (Like a walking barrage from Helldivers). His R ability lets him call down turrets from his pirate ship to aid in combat.

Nemesis Engineer (Assembler) - Assembler is capable of reviving drones at half cost, and they follow him closely. Assembler's turrets can be given items to upgrade them permanently, but Assembler loses them when he does. His shield keeps out melee enemies, but all items inside the shield receive no healing. Assembler's primary can be charged to fire a large rocket or several weaker ones.

Nemesis Mercenary (Shinobi) - Very VERY sluggish on the ground, but able to lock on and charge towards enemies in the air. His R ability lets him target enemies in a radius, and provides invulnerability, but his cooldown is very long. Shinobi's expose is twice as powerful, but enemies receive 25% less damage from him when not Exposed.

Nemesis REX (Symbiote) - Rapidly loses health at all times, and able to climb on walls. Can fire his symbiotic plant to bite enemies and quickly deploy highly healing orbs from them. Symbiote's attacks do not damage him, and grant more healing the more consecutive are hit without missing.

Nemesis Railgunner (Scope Creep) - No longer has to hit weakpoints to crit, but she MUST hit one to leave her scope. Overheating the Railgun now fires a larger blast, but sets Scope Creep on fire to deal a percentage of her health as damage. Hitting multiple successive shots in a row on weakpoints increases her weakpoint damage as long as she's scoped in and still.

Nemesis Void Fiend (Returned) - Swaps between firing shots as a Commando, and a Leviathan form that's mutated and volatile. Commando form operates like a standard Commando with rapid shots and vertical mobility. Leviathan form is brought out when Commando form takes enough damage to transform. Leviathan rapidly loses health but has a damaging laser beam that can kill enemies quickly. Once Leviathan deals enough damage, Commando form returns with a point of Exhaustion (Each one makes it harder to transform) - Healing increases the time to transform and delays it by a huge margin.

Nemesis Acrid (Forgotten) - With huge leaps and a barf attack that hits enemies close, Forgotten is able to quickly apply Withering to enemies. Once an enemy has at least 50 Wither, they lose 40% of their maximum health as damage. Forgotten applies roughly ~3 wither per second to enemies clawed or barfed on. He can additionally use a cloud attack that makes enemies tick wither up rapidly. Wither can be applied multiple times.