As an alternative to the classic magic-user, wizard or mage, why not use these variant magic ‘systems’; compatible with any RPG since the ‘rules’, such as they are, use the basic class structure as their framework.
Both these variants use the magic-user class for experience, saving throws and the like. When it comes to spells, the number of spells per day is how many potions of ‘junks’ that can be created or used during the course of a day; they gain new recipes or learn how to make things from junk better, with level gained (instead of gaining new spells). Hit Points, starting gold, and the like are all as per the normal rules for magic-users (in whatever system used).
Of the art of potion brewing, and quaffing
A quaffologist is a brewer of potions, both magical and mundane. Given a skin of water, even wine, some herbs and the right ingredients, and a quaffologist can brew up a potion while the cleric cooks up a meal. Each potion is a one-shot effect, simulating a spell from the magic-user list.
When a new spell is allowed, a qauffologist learns a new formula and can brew more potions; instead of memorising a spell for the day, the quaffologist spends time brewing his potions. These simulate a normal spell, determined as normal from the magic-user list. For beneficial spells, the target drinks the potion for the spell to take effect; for attacking spells, the potion is instead thrown like a grenade: for instant hit spells, such as magic missile, the fluid inside leaps out of the broken bottle and flings itself (as if alive) at the target and takes affect as normal.
Of the study and implementation of making things out of junk.
A junkologist can make things out of junk; improvising and jury-rigging whatever is at hand to build whatever is needed. Known as ‘junks’, these temporary items seldom last once they are used, but the remnants can be recycled back into the junkologists’ box of tricks (like a spell book, but is in fact a box full of junk).
Instead of casting and memorising spells, a junkologist can create something out of whatever is at hand (or in her box) a number of days equal to the number of spells per day this magic-user variant normally has. The built ‘junk’ can only be used once, but the pieces that are left are put back into the box to be used again. Some of the pieces might have be to knocked back into shape, or tinkered with over night, so there is a limit to how often such builds can be made.
Each ‘junk’ can duplicate an object, such as a weapon, a key to open a lock, a makeshift bridge, a grappling hook and rope; anything that the player can think of and that the DM approves. There are limits, determined by the ‘spell’ level of the created junk, as per the following table:
||Chance of Success
||Boost to Ability
||2 in 10
||3 in 10
||4 in 10
||5 in 10
||6 in 10
||7 in 10
||8 in 10
||9 in 10