A dual progression prestige class is one that progresses two class features, usually spellcasting, manifesting, invocations, etc. at once. These prestige classes are typically intended for multiclass characters who want to progress the features of two classes (though there occasionally exist ways to enter the class without being multiclassed).
Prestige classes such as the Arcane Trickster would fall under what I am looking for, because they are progressing Sneak Attack and Spellcasting, it is a class for multiclass characters intending to progress the features of two separate classes together.
The progression of Spellcasting is typically denoted in the "Spells Per Day" section of a prestige class' features, as well as in the progression chart.
The obvious and perhaps most iconic Dual Progression prestige class is the Mystic Theurge from the Dungeon Master's Guide:
When a new mystic theurge level is gained, the character gains new spells per day as if he had also gained a level in any one arcane spellcasting class he belonged to before he added the prestige class and any one divine spellcasting class he belonged to previously.
Mystic Theurge, obviously, is a dual progression prestige class for Arcane/Divine.
Here are the other prestige classes I am aware of that have a dual progression mechanic:
- Mystic Theurge (Arcane/Divine)
- Ultimate Magus (Spontaneous Arcane/Prepared Arcane)
- Fochlucan Lyrist (Arcane/Divine)
- Cerebremancer (Arcane/Psionic)
- Eldritch Theurge (Arcane/Invocation)
- Eldritch Disciple (Divine/Invocation)
- Arcane Hierophant (Arcane/Divine)
- Arcane Trickster (Sneak Attack/Arcane)
- Sacred Fist (Unarmed Strike/Divine)
- Rage Mage (Rage/Arcane)
- Jade Phoenix Mage (Arcane/Manuevers)
- Ruby Knight Vindicator (Divine/Maneuvers
- Anima Mage (Arcane/Vestige)
Are there any dual progression prestige classes that I am missing?
A small note, technically classes that progress full or 3/4ths Base Attack Bonus and Spellcasting ability are considered dual progression classes, such as the Abjurant Champion or the Eldritch Knight. The logic being that they are progressing both martial ability and spellcasting ability. However, there is an extreme amount of "Gish" prestige classes, so I suspect there would be too many to list.