Here’s one we never used, and I’m still not using right in this campaign: Magic-User Chance to Learn Spells.
Here’s how it works in 1st edition AD&D: You roll up your M-U and look at your Intelligence. You’ll get a percentage. You go down the list of 1st level spells and roll for each. If you succeed on a spell, it is possible for you to cast it eventually. You still need to find the spell to put in your spellbook. This is part 1.
You also have a Max and Min spells per level. This way, out of a list of 30 spells, you won’t know none and you won’t know them all. If you hit your Max, you stop rolling. If you get through the list and haven’t hit your Min, you go through again and reroll for ones you failed on.
This is stupid.
First off, you’re least likely to know spells that start with later letters. Huh?
Second, people typically say something like “how come if I’m stupid I can’t have a big library” but this isn’t about the books you own. It’s about the books you understand. I can see an M-U saying “yeah Web? I never could get the hang of Web” and he has a spellbook with it but just can’t memorize it. But the presentation doesn’t explicitly say this.
Third, why limit the M-U on which spells he can use? It’s bad enough that he has to find the spells, and then memorize only a small number at once. Here’s my main gripe with the system: it adds a whole extra step to the M-U process.
1: Roll for spells you can learn.
2: Try to find the spell so you can put it in your book.
3: Choose which spells from your book to memorize.
4: Choose which of your memorized spells to cast.
This is way too many steps. I have new players look at me and ask “okay, so which spells do I have?” and the answer is a huge pain in the butt.
I think Chance to Learn Spell is usable in two ways.
First, the way I use it in the current 1st ed game, you roll it when you transcribe your spell into your spellbook. Failure means you burned the scroll up without successfully transcribing the spell. It’s still fiddly and I included it only because I was determined to use all the rules I could from the books.
Second, you could use it as-is but roll only when the M-U first encounters the spell in question (not when you get access to the new spell level) which makes it a lot less of a hassle. The M-U slowly becomes a specialist in certain spells, though a hodgepodge, which makes each M-U different and interesting. When not everyone can use Fireball, Fireball is no longer the boring default.
I would pair this with specialization so you choose a magic school and you get +25% to your learn chance for that school and -25% to all others. This way you can legitimately play a Fire Mage or a Diviner or whatever and be reasonably certain you will be able to use the spells in your specialty. It’s like making a custom spell list for your subclass except it develops organically. I’d also cram all the Illusionist spells into the M-U list and delete the Illusionist class entirely because he’s been subsumed. This also involves strategy on the part of the M-U player: I can try to learn this non-specialty spell, but the chance is low and even if I succeed this represents one of the few spells I have left after I learn all my specialty spells in this level. So, if I’m a Transmuter, and I want Fireball, I’m basically choosing Fireball instead of some other spell and I’m not even guaranteed to be able to learn it.
I’d like to see Cleric subclasses besides Druid develop similarly: specialized spell list and a couple special abilities. It’s what 2E did but I see people ignoring their allowed spheres way too much and besides too many spheres are allowed anyway.