D&D 5E has many sub-classes to choose from, spanning several core books. Here are some quick summaries of each subclass, which will give a bit of insight to the theme, generalized game mechanics, and the likely play style to expect. This list isn’t the way you are expected to play the subclass, but our own interpretation of what the subclass archetype is trying to be. Your interpretation may differ, and if it does, please share how!
Alchemist (Eberron / Tasha’s)
Theme: A mixologist of magical potions, serving lively libations with a side of the arcane.
Game Mechanics: Begin with proficiency in alchemist tools, and the ability to create experimental elixirs. The elixirs have random effects such as healing, increase speed or resistance, saving throw bonuses, ability to fly, and altering their appearance. At level 5, your healing and damage spells have increased effectiveness. At level 9, your elixir always has bonus healing, and you have an extra pool to cast lesser restoration. At level 15, you gain resistance to acid and poison, cannot be poisoned, and can now cast greater restoration more easily.
Play-Style: You’re the type to try new things with friends. You like playing a supportive or healing character, with a touch of chaos and unpredictability.
Theme: Literally embodying magic, the Armorer wears their magic, as though they are an infusion of their own spellcasting.
Game Mechanics: Start with being able to wear heavy armor and proficiency with blacksmith tools. You also start with arcane armor, which can be any armor you find and then cast this spell on it, removing strength requirements, allowing the armor to be your arcane focus, able to replace any missing limbs, and cannot be forcibly removed. You also choose one of two types of arcane armor: one giving extra hit points and melee damage, the other allowing ranged lightning attacks, increased movement, and stealth benefits. At level 5, you can attack twice in combat. Later, at level 9, your armor counts as 4 items to infuse rather than 1. At level 15, your armor gains an extra ability; either drawing enemies closer to you and allowing a melee attack, or for your ranged lightning attack to grant advantage and additional lightning damage.
Play-Style: Your favourite part of the artificer is likely the additional magic items, and that you want to be able to change and literally wear even more magical items.
Artillerist (Eberron / Tasha’s)
Theme: Carving firearms with arcane energy, the Artillerist uses magical guns as their spellcasting focus.
Game Mechanics: Start off with proficiency in woodcarving tools, and an eldritch cannon. The cannon can be a long ranged weapon like a ballista, an area of attack weapon like a flamethrower, or a protection creator that gives temporary hit points. At level 5, you can turn a wand, staff, or rod into an arcane firearm which can cast your spells, giving extra damage. At level 9, your cannon’s damage increases, and you can make your cannon detonate, causing a large explosion. At level 15, your cannon provides half cover to nearby allies, and you can create two cannons.
Play-Style: You want to use both guns and magic. Or just one really, really, big magical gun.
Battle Smith (Eberron / Tasha’s)
Theme: Battle smiths create both weapons and companions with their magical technology. With a high concentration on damage output, they still maintain a wide versatility with spells and support.
Game Mechanics: Begin with proficiency in smith’s tools, and martial weapons, which you can use your intelligence modifier instead of strength or dexterity. You also start with a Steel Defender: a constructed companion which comes with it’s own stat block. At level 5, you gain an additional attack. At level 9, you have a limited pool to do additional damage or heal an ally when you or your companion deal damage. At level 15, your additional damage and healing increase, you gain additional AC, and your companion gains a slight buff to do additional damage.
Play-Style: You want to be versatile with magic and weapons, but with a focus on a companion. You probably really like the idea of having a familiar, but wish they could be stronger.