I haven’t seen the anime but here are the opening and closing credits above and below for the live action adaptation after each episode for those curious. Each member of the cast and their rival team’s members mains one of the 25 classes that are highlighted in these vids. You’ll get familiar with the them and their abilities because they are repeatedly shown throughout the series.
Unspecialized - jack of all trades since it has the abilities from each class but at a lower proficiency
Battle Mage - has spells that directly enhance melee combat, can summon fire dragons to throw as a projectile from afar
Launcher - long range artillery, can switch to dual pistols up close
Ghostblade - support that has spells like freezing enemies a la Sub Zero
Warlock - ranged spell caster, can imprison enemies, channel purple rain from the sky, summon a death gate
Witch - ranged that fights hovering on a saucer in the air, mostly harasses with debuffs
Cleric - basic healer
Summoner - can summon beasts
Brawler - Wolverine like class equipped with claws and throws bricks lawl
Ninja - the rogue of the game they play, can vanish and sneak attack
Knight - melee with high HP and defense
Sharpshooter - long ranged sniper
Mechanic - fights using gadgets, missiles, and bombs and can also fly
Striker - melee that reminds me of Vi from LoL
Qi Master - sword wielding melee
What’s missing from WoW from my experiences these days is having guildies and teammates like these. I reflect on my WoW days from way back after watching this show and I could relate just being around people so passionate about the game and each other. If somehow the past magic into the game and it’s players could be rekindled again. 
