Posthumans

Not goblins; goblyns, from the Ravenloft setting. They're confusingly named, but completely unrelated to goblins. "Goblyns are hideous creatures with slightly bloated heads, pointed ears, and glowing red eyes. They have long, mangy hair which grows only on the back of their head and necks. About half of their face is taken up with a wide mouth full of needle-sharp teeth. These creatures are formed by powerful evil magical items and spells which transform humans into these twisted beings. This transformation causes them to become very evil and totally submissive to their master's every whim. Goblyns have a telepathic link with their master and, through him, with all of the other goblyns he controls."

Other Ravenloft posthumans: darklings, ermordenung, quevari, bruja (maybe), moor men, shattered brethren, vorlogs. Vampyres are not vampires: they are fanged, blood-drinking humans, but they are not undead.

One of the creation myths in the Dragonlance setting goes like this: once there was a race of clever humans called the Smiths who worshiped Reorx, god of the forge. But the Smiths grew prideful and arrogant, and as punishment they were transformed into the minoi, or tinker gnomes, cursed to be obsessed with inventing but only capable of making flawed, overly complicated, perpetually breaking devices. Much later, a magical gem filled with the power of wild magic, the Greystone of Gargath, was released in the world and the gnomes traveled across the world to capture it and use it to power their Great Machine. After years of pursuit, they made siege upon the fortress of Gargath, where the gem was temporarily housed, and accidentally built a siege engine that destroyed Gargath's walls by falling on it. Coming into the presence of the Greystone at last, those gnomes who desired the gem out of greed were transformed into dwarves by the wild magic of the artifact, and those who desired it out of curiosity were transformed into kender.

There are other myths. Some say the kender were not gnomes, but the gnomes' elven allies. Some say the gnomes and dwarves were not cursed humans, but descendants of an older, elemental race called the Smiths who were born infused with the wild magic of creation. But the above is the most common myth told in Krynn.

I mentioned the parai because I decided to include in my list all monsters who could transform humans into members of their own kind. Thus: meenlocks, vargoilles, lycanthropes, ophidians, undead, parai, and even red slaadi include posthumans among their number. Not all of them are posthuman, but some of them are.

Other posthumans: the aventi and darfellans from Stormwrack, the asherati and perhaps the cursed cold ones from Sandstorm, manscorpions, qauriks, the Traldar from B10, the psion uncarnate from the EPH, and azurins from Magic of Incarnum.

Empty Vessels of the Inspired (selectively breed humans which serve as ideal vessels for a Quori), Daelkyr Half-Blood/Foulborn, some "Foulspawn" (generic 4e parlance for grouping of creatures warped by the Far Realms) varieties, Shades, Vyrloka (which are likely the same things as Vampyres), and many possible types of plane-touched.