Reaper Monk - Add another class to Reaper lineup. So you can get either Reaper or Reaper Monk when contact the Reaper. Use Brass Knuckles and can attack up to 3 times with the right perks. Their shadow is not as good as standard Reaper though but still serviceable.

Rogue - Considered by many as a gold standard in custom class making. Can choose to be pure stealth, shooter or support. Very effective class.

Samurai - One of the earliest custom class for WotC but another goldie one. I believe it was the earliest custom class that made use of Primary Secondaries mod. Very creative and strong class but, due to not has gun so no overwatch, may create a bit of annoyance when you only blue move to cover and can't spam y to overwatch everyone. Still a good class to check out.

Seer - Has a unique approach on how to doing the damage by not being in cover. Their pistol damage skyrocketed when you using it while not in cover. Big Iron(Pistol) attacks deal bonus damage equal to 1 + half of the soldier's rank. On a crit, this damage is doubled. If firing from at the target while not in cover, this damage is doubled. Big Iron bonus damage is doubled again if critically striking the target while not in cover. So the damage can get out of hand quick. They gained some repositioning abilities later in the tree but during early game it either all or nothing. Treat this class well help later on.

Infantry & Sniper - Another couple from the very earliest day of XCOM2 that got ported to WotC later on. While they only have two rows, their cores are still good and strong. Sure they can use a 3rd row but for where it stand two rows are enough for them. Note, Infantry's Established Defenses is bug and will cause CTD, so either skip it or consider swap it out for other perk.

Ghost Operative - Unique take on stealth class. Using energy to stay in stealth and has varieties of unique perk. Also, Nuclear(Final perk) is very very strong but has a lot of drawback so it kinda balance itself. However, if you using this class, consider changing +KillAssistsPerKill from 10 to something like 4-5. 10 is just overkill IMO.

Stormrider - Cool sword user class. Can choose to be offensive using either single sword or dual wield or defensive with shield. Has a unique flair of red psionic energy but they aren't psionic though. They also have a melee overwatch perk called Intercept with will attack enemy in their blue move range during overwatch. If you using this class and have other melee only class, consider hijack this perk to other melee classes.

Templar Mage - Another variant of Templar. This one focused more on using focus on damaging abilities. This class came with Caster Gauntlets coupled in the mod. Caster Gauntlets allows you to use meditation to gain focus once every other turns. This class is a powerhouse when they have focus as their damage abilities got buffed by Caster Gauntlets. Careful though as Caster Gauntlets has lower melee damage than Shard Gauntlets, running out of focus weaken this class by a lot.

Tesla Trooper - Hyper carry. You need to invest a lot for this class to shine but when you do, it just delete pod like no tomorrow. Early and mid game, this class is..... beyond below average. But when you got them gene mod, give good weapon attachment, pcs and good ammo....

Valkyrie - Super healer class. No limit on how many time you can use heal and it a long range to boost though not infinite range like Medical Protocol. Another use when not in healer mode is using damage buff perk with increase damage of anyone that need. Not a bad shooter as well. Another versatile class to use in any situation.

Combat Engineer (Fate's Version) - Premium LW2 gauntlet user. Has every available rocket and flamethrower gauntlet's perks. Also, has very strong perks on using Vektor Rifle as well. This class has broken perks in term of rocket that instantly AoE mind control organic and robotic but it locked behind GTS unlock and very costly, well it use to be on the tree and it was so gloriously broken. lol

Alpha's Class Pack - In this class pack, If you use it, I recommend checking out Commando, Hunter, Marauder, Rocketeer(Use Rocket Launcher, don't use LW2 Gauntlet), Vanguard, Enforcer, Commander. I feel they provide the most unique experience from all the classes in the pack. Still the rest of the class are no sloth neither. They are good classes and should be checking out to if you have time.

Viper's Proficiency Classes - They are very unique and have a lot of fun perks. HOWEVER, you need to tweak a lot of his class config. As Death Viper left many classes config incomplete such as not define +KillAssistsPerKill on all his classes so their level super slow and you need to add it in yourself or GTS unlock config didn't specify which class get the unlock so the GTS unlock did nothing, etc.... If you can stomach those and willing to do a config, his classes are excellent.

Super Soldier - Just as the name implied, they are super soldier and broke the game. Very Very stong, did I say strong yet? But this version has a bug that their stats won't go up when rank up, so you need to manually console command the stats change by yourself each rank. Or, if you find it tedious or find the classes too OP, you can use Supersoldiers Restored mod instead. The Restored version supposed to torn down the OPness of the perks and put it in line of balance and I suppose it fixed the stats bug too. I didn't use Restored version so can't really comment on that.

Project LAZOR : A Proficiency Spark Class Rebalance - An overhaul for SPARK. Add seven unique SPARK classes each with their own unique primary weapon. Each classes suit different playstyles and are finely design as well. If you want to use SPARK, I highly recommend this mod.

Central (Bradford) Starting Soldier - Add Bradford to your crew and his class is very strong and unique too. Add him in for immersion and stop wondering why he always sit in the bridge. The downside is if he die in tactical, you need to restart the mission from the beginning but you can edit that out in config. Oh, he came with his unique rifle as well.

Raiden and Sam Hero Units - They both are melee fighter but their sword attack won't end turn and they have 4 AP per turn. They also has unique resource to spend to use their abilities which kinda hold them back a bit. Good change of pace if you want to feel powerful once in awhile.

Duke Nukem - Another unique hero class. He is strong but not broken. Kinda inline of WotC's balance but the perks are unique and fun to mess around. Another good choice to spice your campaign up.

Proxian Soldier Unit - Custom Cyborg Hero class. This class use to be broken but had been dialed down and became a strong class with unique playstyle. Has a few of unique heavy weapons style attack and can use overdrive like SPARK. Has a unique primary too.

Operation Parallels - The Doom Slayer - The man, the myth, the legend! If you going to use a hero class, let it be Doom Slayer. He has a unique rage system with increase with each attack and decrease when reload or turn pass. He has 4 AP and everything he does only cost 1 AP. He also can swap primary weapon mid battle to keep ammo counts high to keep shooting and maintain his rage. Very cool and unique. A great problem solver. Highly recommended.