So, one of the things that I always found just goofy about AD&D was the notion of scrolls – it was wierd enough for mages but for clerics it was even worse. A spell or a prayer is written down and then when it is read off again, the spell takes effect?
But spellbooks are different?
And magic items are different?
So many years ago I changed mage scrolls into imbued/embedded spell crystals called “D’Lanni Stones” – essentially saying that were akin to one-shot Rings of Spell Storing. This worked pretty well, and even now matches well to the way that I treat spellbooks. They work and are rolled up exactly the same as normal scrolls, they are just stones instead – and the Write spell can be used to translate the “mental charge” into a spell formula suitable for a spellbook.
The question then remains as to how to handle things like Illusionist, Cleric, and Druid scrolls?
Treating clerical magic as prayer with a fixed “mana draw” each day rather than Vancian magic changes the way that Clerical “scrolls” might work. In my world, there aren’t clerical scrolls, there are instead monstrances, icons, amulets, and relics charged with divine power that give the devout bearer an extra number of prayers – either defined by a total number of spell levels, or by spells defined by level and number. These are also deity/pantheon specific, so a Lightbearer of the Society of Light isn’t going to be able to use an item associated with the Dread Court unless one of that pantheon lets them (and the Sarim are likely to be a little iffy about *that*…) – which somewhat limits use – though destroying it might grant some experience! They also rarely allow access to spells (prayers) beyond the level that is normally allowed to the cleric – there are such items but they are much more rare and tend to be specific spells rather more generic in nature.
Ok, so Druids, being more akin to Mages in the way that they use magic, use “Rune Sticks” – which have been carved with Ogham staves and charged with mystical power and these operate just like normal D’Lanni Stones. Technically speaking, they also have access to Clerical style items, though these are rare and valued highly.
Illusionists are another weird case in my game world, since they aren’t really mages or clerics but a type of psychic instead. So they merely use a variety of substances (incense/smoke, serums, dusts, elixirs, potions, etc) to temporarily increase their “spell-casting” potential for the day (I suppose should get off my butt and figure out a term for what it is that they do). These are generally immediate effects, but some rare and exotic versions allow the “spell” to be held for rounds or turns or even hours before being discharged. These substances also come in two varieties, generic spell levels and specific spell effects – these latter versions are the only way that Illusionists have to cast “spells” beyond their normal level.
For what it is worth, Psionicists have a handful of items similar to Illusionists that they can use to boost power or restore psychic strength but they don’t have anything that operates like a scroll – allowing them one-off use of a Discipline, Science, or Art.