So, I do love M20 - it's a beautiful stripping back of all the crappy stuff from 3rd edition, bringing it back to its roots. But I find that the sample spell lists are a little constraining - and it leads to Wizards feeling very similar in the long run. The problem is worse for Clerics - all Gods grant the same spells? Not likely, methinks. So I'm putting together a few "stripped down" versions of some classic Mage and Cleric archetypes, to help expand the horizons of any Magic-Users in your campaign.
First - the Necromancer! Heavily inspired by the Heroes of Horror Dread Necromancer Base Class, I've had to hack in a few extra rules to the light framework of M20- fingers crossed they don't change too much.
Acid Splash - 1d3 acid damage.
Detect Magic - detects spells and magic items within 60 ft.
Disrupt Undead - deals 1d6 damage to undead.
Ghost Sound - figment sounds.
Mage Hand - 5-pound telekinesis.
Touch of Fatigue - subject gains a -1 penalty on all Strength or Physical rolls (including combat) for 1 round/level.
Cause Fear - 5HD creatures flee for 1d4 rounds.
Chill Touch - one touch/level deals 1d6 damage, and target must make a STR+Phys roll or take a -1 penalty on all Strength or Physical rolls (including combat) for 1 round/level.
Create Lesser Undead - create one Tiny undead creature (see below).
Detect Undead - reveals undead within 60ft.
Hide From Undead - renders you invisible to Undead creatures for 1 round/level (intelligent undead get to make a MIND+Knowledge save).
Inflict Light Wounds - 1d8 damage +1/level (max. +5), can be used to heal Undead.
Blindness/Deafness - makes subject Blinded or Deafened.
Command Undead - undead creature obeys your commands for 1day/level.
False Life - Gain 1d10 temporary hp +1/level (max +10), cannot be used to cast spells (as other magical healing).
Gentle Repose - preserves one corpse for 1 day/level.
Ghoul Touch - Paralyzes one subject, which exudes stench that makes those nearby sickened (STR+Phys roll or throw up and lose your action).
Inflict Moderate Wounds - 2d8 damage +1/level (max. +10), can be used to heal Undead.
Dispel Magic - removes magical effects with a successful Magic Attack (MIND bonus+ Level).
Halt Undead - Immobilises 1+1/2level Undead for 1 round/level.
Inflict Serious Wounds - 3d8 damage +1/level (max +15), can be used to heal Undead
Ray of Exhaustion - target must make a STR+Phys roll or take a -3 penalty on all Strength or Physical rolls (including combat) for 1 round/level.
Speak With Dead - corpse answers one question/two levels.
Vampiric Touch - touch deals 1d6/two levels damage; caster gains half damage as HP.
Animate Dead - create skeletons and zombies (max 4HD on Undead/casting).
Black Tentacles - tentacles grapple all within 20 ft. spread.
Dispel Magic - cancels spells and effects.
Fear - subjects within 30ft. cone flee for 1 round/level.
Inflict Critical Wounds - 4d8 damage +1/level (max +20), can be used to heal Undead.
Poison -deal 1d10 STR damage, extra 1d4 after 1 min.
Cloudkill - cloud of gas kills 3 HD or less; 4-6 HD save or die, 6+ HD take Con damage - can be moved by using your action for the round. Lasts 1 round/level.
Inflict Light Wounds, Mass - 1d8 damage +1/level to 1 creature/level.
Magic Jar - enables possession of another creature.
Nightmare - sends vision dealing 1d10 damage, fatigue.
Raise Dead - Restores life to subject who died as long as one day/level ago (Gentle Repose "freezes" this timer).
Unhallow - designates site as Unholy (Magic Circle Against Good, -4 penalty to Turn Undead, other effects at GM's whim).
Acid Fog - fog deals acid damage (2d6/round inside the fog).
Anti-Life Shell - 10ft. heishpere keeps out living beings for 10 mins/level.
Create Undead - create Ghouls, Ghasts, Mummies or Mohrgs (max 6HD of Undead/casting).
Harm - deals 10 damage/level to subject, can be used to heal Undead.
Inflict Moderate Wounds, Mass - deals 2d8 damage +1/level to 1 creature/level.
Undeath to Death - Destroys 1d4/level HD of undead (max 20d4).
Banishment - banishes 2HD/level of extraplanar creatures.
Control Undead - doubles the amount of Undead you can control for 10mins/level.
Create Greater Undead - create Shadows, Wraiths and Spectres (max 7HD of Undead/casting).
Finger of Death - kills one subject.
Inflict Serious Wounds, Mass - Deals 3d8 damage +1/level to 1 creature/level, can be used to heal Undead.
Symbol of Weakness - triggered rune causes 3d6 STR damage to creatures within 60ft, lasts 10mins/level.
Clone - duplicate awakens when caster dies.
Horrid Wilting - Deals 1d6/level damage within 30 ft.
Inflict Critical Wounds, Mass - deals 4d8 damage +1/level to 1 creature/level, can be used to heal Undead.
Symbol of Death -triggered rune slays 150HP of creatures within 60ft., lasts 10mins/level.
Trap The Soul -imprisons subject within gem.
Unholy Aura - +4 to AC, +4 resistance, and SR 25 against good spells, to you and allies within 20ft, for 1 round/2 levels.
Astral Projection - projects you and allies to the Astral Plane.
Harm, Mass - deals 10/level to one creature/level.
Soul Bind - traps newly-dead soul to prevent resurrection/passage to the afterlife.
Wail of the Banshee - kills one creature/level in a 25ft +5/level radius (STR+Phys to resist).
This spell list introduces something previous M20 lists have shied away from - summoning spells. They were part of what left the 3.5 "action economy" a shambling borked mess, and I'd say Greywulf was right to remove them. However, the Necromancer has a bit less offensive potential the other list has - so, hopefully, by removing one feature, we can incorporate another without affecting the balance too badly. I've limited the number of Undead you can have under your control at any one time, halfing the 3.5 amount (which could honestly lead to you being in control of an army at low levels).
I also added a new spell (seemed weird that you couldn't animate dead things, even partially, until higher levels).
New Rules and Spells
Where a spell requires a saving throw, I've tried to follow the SRD and add it in M20 terms, but, should I be not the most vigilant writer and miss one, here's a quick list of what you might need to know:
Difficulty - usually 10+Caster Level+Caster's MIND bonus, but you can adjust these for NPC spellcasters, or just pick a number out of the air for traps, etc.
Fortitude save - roll STR bonus+Physical
Reflex save - roll DEX bonus+Physical
Will save - roll MIND bonus+level.
You can control up to your level in Hit Dice of Undead at any one time (plus one extra with Command Undead, doubled with Control Undead). Most Undead can only follow simple instructions, but this one's up to your GM to figure out, based on the intelligence/MIND score of each individual Undead.
On your turn, you can give up your action to specifically control one Undead under your control - otherwise, they follow your orders, and are controlled by the GM as far as how they follow them. For example, Undead commanded to "Attack my enemies" will attack the nearest enemy they can reach - but, by sacrificing your action, you can command one Undead to target a specific creature or enemy.
Most will use their basic forms of attack - to use any special abilities, you'll need to command them. Again, this is all subject to the whims of the DM, so be nice and buy him pizza.
Create Lesser Undead
Material Components: One Tiny corpse, or a pile of bones and materials
You suffuse a small pile of bones, scraps of flesh, and rags with a local spirit - perhaps a small animal you have recently sacrificed for this purpose, or a spirit located with Detect Undead. You create one Tiny Undead, with the following profile:
1HD (1d4HP), Bone Spurs -3 (1d3-1), +3 Phys or Subt
This creature can only follow very simple vocal commands ("Stay here", "Follow me", etc), and if uncommanded, will simply stand motionless.