Here is a class that I have been working on for inclusion in the basic game.
The sorcerer is a magic-user that has natural arcane talent. He does not study magic or keep a spell book. Rather, his spells are natural talents, and often manifest themselves in idiosyncratic ways. Some sorcerers must engage in particular activities in order to trigger their abilities (e.g., dancing or drawing runes), while others must merely concentrate (decide during character creation). Spells that require somatic components in the rules still require some bodily movement, though the nature of that movement should conform to sorcerer in question. No sorcerer spells require material components. Sorcerers can not create magic items.
The sorcerer uses the same spell progression table as the magic-user, but does not need to memorize spells. Instead, he accumulates a number of spell slots equal to the value of each spell he has access to. For example, a third level sorcerer can cast two first level spells and one second level spell. Thus, he has 4 spell slots, and can use these to cast any combination of spells the level of which he has access to. This wizard could cast 4 first level spells, 2 second level spells, or 2 first level spells and 1 second level spell. He regains use of all spell slots after an extended rest. (I’m not sure about this method of regaining spell slots, but I don’t have any other ideas right now.) Perhaps some sort of active recovery would work better.
A sorcerer may cast the same spell more than once, but each time it is cast, the cost in spell slots increases by one. For example, say that a sorcerer has the sleep spell. The first time he casts sleep, it uses up one spell slot. The second time he casts sleep, it expends two spell slots, the third time, three slots, etc. I’m quite happy with this mechanic, because it encourages the use of more than one spell (the danger with spell point systems is that the caster might merely employ fireball after fireball, which limits creativity). It also reflects the way the sorcerer’s casting is less precise and systematic than a scholarly magic-user.
Once per day, the sorcerer can let loose wild energies and cast a random spell. This uses up all remaining spell slots, with level balance being made up by damage. The spell cast thusly may be of any level, even a level that the sorcerer can not yet cast, but the targets and all details are up to the referee. Such random spells may only be cast during a time of great stress, such as during combat. I’m not sure about this ability yet, but I really like the flavor. Perhaps the random spell should not be of any level, but rather the sorcerer’s level + N (maybe N = 3?).
There is a 50% chance that a critical failure results in a spontaneous spell discharge of one of the spells the sorcerer can normally cast. The wild magic drains spell slots if available, and if they are not available, the balance is made up by damage.
A sorcerer can not be killed by damage from his own spell casting. Instead, if such damage reduces him to 0 HP, he is knocked unconscious and is stable at 0 HP.
The sorcerer can use leather armor but no shield and simple weapons. Club, short sword, light crossbow, spear, quarterstaff, dagger.
Other similar ideas: