D&D 5E Generating spellcasters

[Fenris-77]

I don't use "classes" for my NPCs, but for spellcasting support I usually use the following:

Shield
Mage Armor (precast)
Magic Missile
Armor of Agathys (skinned to a damage type that suits the caster)
Hellish Rebuke (also skinned)
Web
Silence
Counterspell (oh, do players hate that!)
Fireball (reskinned in damage type and shape to suit the caster, always gets the player's attention)
Haste (when the number of arrows coming at the PCs jumps from 2 to 4, and they ask if there are more archers, and I get to say "No, they're just shooting a lot faster all of a sudden" makes DMing worth it.)
Spirit Guardians (just as annoying when the NPC has it)
Enemies Abound
Greater Invisibility
Banishment
Dimension Door (if you want to save the NPC for another time)

I'd add flaming sphere, blindness/deafness, expeditious retreat, fog cloud, and some illusions to that list.

 

[Paul Farquhar]

The PC spellcasters are raising havoc. The party is about 8th level, which means a lot of spell slots. I need to bring some AoE and buffs into play to level the playing field.

You just need a bunch of level 5 casters packing counterspells.

Monster Manual p347 Mage, p 348 Priest.

 

[Maestrino]

Is there a way to justify adding magic resistance/immunity to the monsters? Or just using monsters that are resistant to a lot of magical effects (golems/constructs, things like Rakshasas that can't be affected by a spell unless it's 7th level or higher...)

 

[TwoSix]

I tend to avoid illusions, because it's enough of a challenge to present my players with a coherent sense of place with some of the wacked-out concepts I put them through. If I give them false information on top of that, they'll be totally lost.

I also tend to shy away from hard save or suck spells like blindness, as they either save (which isn't intimidating), don't save (which just slows the fight down), or get lesser restoration (which just becomes a spell slot trade, and also slows the game down). It's not a bad one to mix in once in a while to make the healer feel good, though, especially if it's upcast to target 3-4 PCs.

The other spells are all excellent choices, though.

 

[MechaTarrasque]

Adding a couple of levels warlock to a monster can be helpful. They don't know a lot of spells and have few spell slots, so it doesn't add much burden. If I am feeling particularly lazy, most of their noncantrip spells are just the pact spells, although I like to get summon minor demons and arms of hadar in case the PC's get too close.

For invocations, after agonizing blast and repelling blast, I would pick the ones for your pact implement or the ones that give you a new spell but require a spell slot for.

If none of the PC's are bear totem barbarians, I would stick with tome (if the NPC was for only 1 fight) or chain (if the PC's will encounter the NPC more than once).

 

[Paul Farquhar]

There are quite a lot of warlock stat blocks in published sources (Volo's is full of 'em). You know what there isn't? Sorcerers (apart from the odd kobold).

Warlocks aren't great as anti-casters though.

 

[Fenris-77]

I'd probably take the spells I mentioned, but I might not use them all in a given fight. What I'm looking for there is the best toolbox. Just like a player I want to make sure I pay attention to action economy when I'm building the list. Illusion specifically I might or might not use, mostly the choice coming down to how experienced my players are. The better the player the cooler an illusion duel gets. I wouldn't use that with newer players though.

 

[dave2008]

Not stat blocks, but spell lists.

The stat blocks have spell list in them. Or do you want spell descriptions too?

 

[TwoSix]

I'd probably take the spells I mentioned, but I might not use them all in a given fight. What I'm looking for there is the best toolbox. Just like a player I want to make sure I pay attention to action economy when I'm building the list. Illusion specifically I might or might not use, mostly the choice coming down to how experienced my players are. The better the player the cooler an illusion duel gets. I wouldn't use that with newer players though.

Agreed, action economy is paramount. I tend to give my casters some custom spells that are BAs or rxns to make sure their turns are always substantial.

 

[Horwath]

From Volo's

Cantrips (at will): fire bolt, light, prestidigitation, ray of frost
1st level (4 slots): burning hands, mage armor, magic missile
2nd level (3 slots): mirror image, misty step, shatter
3rd level (3 slots): counterspell ,fireball, lightning bolt
4th level (3 slots): ice storm, stoneskin
5th level (2 slots): Bigby's hand, cone of cold
6th level (1 slot): chain lightning, wall of ice

CR9

maybe add some spell that you can use longer and activate as bonus action like flaming sphere and Melf's minute meteors