These are a few spells focused on the concept of nothingness. Feel free to add.

Reverse Energy Transfer
Conjuration [Healing]
Sor/Wiz 6, Clr 5, Death 4, Psi 5
Casting Time: 1 standard action
Components: V, S, M
Range: Touch
Target: One living (or recently dead) creature
Duration: Instantaneous
Save: Will negates (harmless)
Spell Resistance: No

A very versatile healing spell, reverse energy transfer returns from the Void to the target all energy lost within a certain period of time. This heals all damage dealt to the target within the last 1d4+(1 per 2 caster levels) rounds. This can bring the target back from death; however, using it in this manner causes the caster to become exhausted for 1d4+(1 per 5 hit points under -10 healed) hours. This spell also removes fatigue and exhausted if they were caused in the space of time allotted before the spell was cast.

Material Components: A hollow sphere of glass, in which is a vacuum, which is smashed upon casting.

Nothing Bolt
Evocation (Nothingness)
Sor/Wiz 5
Effect: As Lightning Bolt, but negative damage and 1d4+(1 per 3 caster levels) negative levels and exhaustion.
Save: Reflex partial, Will partial, Fortitude partial

This spell functions as a lightning bolt, except that it shoots crackling bolts of nothingness, rending through the fabric of reality and dealing negative damage equal to that of a lightning bolt, 1d4+(1 per 3 caster levels) negative levels, and exhaustion. The damage can be partially evaded (half damage) with a successful Reflex save, the negative levels halved with a successful Will save, and the exhaustion lessened to fatigue with a successful Fortitude save.

Conjuration (Summoning) [Evil]
Sor/Wiz 9, Clr 9
Casting Time: 1 hour
Components: V, S, F
Range: Unlimited
Target: One living creature
Duration: Instantaneous, indefinite; see text
Save: Will partial; see text
Spell Resistance: Yes

Of the breed of spells used to imprison souls, this is by far the most powerful, as it is the easiest to successfully cast, most difficult to resist, and grants the caster the most power over the target.
* * Upon completion of the spell, the target makes a Will save. The DC may be increased or decreased (DM's discretion) depending on the caster's knowledge of the target and/or any object the caster holds that are of importance to the target. If the target successfully saves, it, is instanly exhausted. *If the target fails, its soul is instantly transported within the diamond sphere. If the sphere's value is not high enough, is shatters and the soul goes free. If it is, the sphere and the soul are both transported to an otherspace pocket in the control of the caster. From this point on until either the target is released or the caster sees fit to release the target, the target is under the caster's complete control, although it will go about its daily business when not under a command.
* * The caster's power over the target is absolute, as he or she controls the target's soul. The target instantly obeys any commands to the best of its ability, even suicidal ones. The caster may even elect to change the target's alignment. If this occurs, the target gets to make another Will save (same DC). If the target saves, the spell ends, signified by the sphere's being shattered. This causes the soul to return to its proper bearer, who is propmtly exhausted (no save).
* * At any time during the duration of the spell, the caster may attempt to kill the target. This is accomplished by shattering the sphere while it is within the void. If this occurs, the target must make a Will save (same DC) or die instantly with no chance of resurrection. If they save, they are instantly exhaused, but freed of the spell. However, since their soul is imprisoned, this is the only way the target can die while under the effects of the spell. (Damage that takes the target below -10 hp is treated as unconsciousness.)
* * Although the target will have no significant behavioral changes; and indeed, will rarely even have knowledge of what has happend to it, it will tend to become extremely maudlin and introspective, often brooding for days on end while carrying out everyday activities. Thus, anyone close enough to the character (DM's discretion) can make a DC 18 Sense Motive to discover that something is wrong. However, they will not be able to glean anymore information than that, given that the target itself most likely does not know.
* * When commanded, the target simply feels an irresistable compulsion to carry out a specific action (but does not feel commanded), and does so. It is plain to close observers that something is amiss, and a DC 15 Sense Motive check is sufficient to discover that. A subsequent DC 18 Sense Motive check will discern that the target is not themselves at the moment, and an DC 25 Sense Motive check will discern that the target is not acting of its own free will. However, condemnation is an exceedingly rare spell, and it will take one with vast knowlege of the magical arts to discern what exactly is the cause of the strange behavior; thus, a DC 35 Spellcraft check (Circumstance modifiers apply, at DM's discretion) will discern the exact nature of the control.
* * No spell short of a miracle, a wish, or a freedom spell will remove condemnation. However, a DC 50 Sunder check will destroy the sphere and release the imprisoned soul.
* * Note: All Will saves made to resist condemnation are made at a +2 Circumstance bonus when the target is on holy ground, and are made at a -2 Circmustace penalty on unholy ground.

Focus: A hollow sphere of diamond with a vacuum in the center worth at least 1,000 gp per level of the target, in which the soul is placed.
Optional Focus: If the target is living, an object of importance to the target, such as a treasured belonging, a lock of hair, or a letter from a loved one.