Planetouched

Planetouched are people from the Prime (of which Fearûn is one of, see Planescape Setting for more details) that have the blood of an Outsider, thus a creature from another plane in their body. Depending on how far the parent stands the creature is considered from a certain race. Though the rules do not entirely take it into account some believe that as the blood diminishes so does the influence, however, it is certain to last for many generations

Planetouched Races

Half-Celestials

A Half-celestial is the direct child of a Guardian (LG), Angel (NG) or Bralani (CG) with a mortal race. Naturally they tend towards good alignments. (MM1)

Aasimar

These are Humans with the blood of Celestials in their veins. However, unlike Half-celestials this can be a lot further away down the bloodline. A great-great-great grandparent might have been a Half-celestial. They tend towards good alignments. (MM1)

Half-Fiends

A Half-fiend is the direct child of a Demon or Devil with a mortal race. Naturally they tend towards evil alignments. Certain special combinations yield special Half-fiends that have extraordinary abilities defining them as a special race. Examples are:

Cambion - The son of a Human father and Demonic mother. (WoSQ)

Alu-Fiend - The daughter of Succubus (= Tana'ri demon) (WoSQ)

Draegloth - The son of a Drow female and a Glaberzu (= Tana'ri demon), combines features of both (i.e. four arms) (MoF)

Tanarruk - Orc sub-race that have demon blood in their veins (MoF)

Durzagon - Grey Dwarf (= Duergar) with a Bearded Devil (= Hamatula, Baatezu) (MM2)

Tiefling

These are Humans with the blood of Demons or Devils in their veins, unlike Half-fiends this can be a lot further away down the bloodline. A great-great-great grandparent might have been a Half-fiend. They tend towards evil alignments.

Fey'ri = a special sub-race that is the mingling of Elven and Demonic blood (MoF)

Maeluth = a special sub-race that comes from the interbreeding of Dwarves & Devils. This would be children of Durzagon's bloodline, though a Mealuth need not be of the Grey Dwarves (FF)

Wispling = a special sub-race that comes from a 'special' adventure of a Halfling with a Demon. They are halflings but with a cruel streak for deadly jokes and a thing for blaming it on others with 'alter self' ability (FF)

Zenythri

These are people with the blood of Lawful Outsiders in their veins and tend towards lawful alignments (note: Justicator, Wind Dukes and Visilight come to mind as possible parents (though the later do not seem to have a sex - this does not always prevents things as can be seen with their sub-race and the Genasi) (MM2)

Mechanatrix = a special subrace of the odd pairing of a Human and a Clockwork being (Modrons or Inevitables). They have a mechanical body part somewhere, like upperarm, lowerleg etc. (FF)

Chaond

These are people with the blood of Slaadi in their veins and tend towards chaotic alignments

Genasi

These are people with the blood of Elementals in their veins and tend towards an alignment depending on what the elemental type was as parent (chaotic for air & fire, and neutral for water & earth).

Memphling

These are children of Human & Memphit interbreeding. This is in practical sense the new Genasi of the 3.5 edition They moved it to the Elemental Memphits instead of the Elements as parents, as Memphlings are more human like and do have a sex (unlike elementals) (PH)

Gloamings

Planetouched by Plane of Shadow, Underdark specific and not seen above ground. They are small and have furry wings, quick average flight, apt at shadow spells and resistant against it, resistant against psionics, can detect portals and daylight sensitive. (U)

An older source actually listed them as a form of Tieflings (presumably than the parent would be a Shadow Fiend (this is speculation!)

Shadowswifts

Very lean Human with added speed, initiative and vision & daylight sensitive due to his connection with the Plane of Shadow (PH)

Wildren

Children of a Dwarf and Celestial Badger bloodline. They are not entirely planetouched as generally do not inhabit a Prime, but they are a race on their own with Celestial blood, so some would count them as planetouched. (PH)

Shyft

These are the children of Humans and a race native to Ethereal Plane (i.e. Githyanki). They look very human and can shift to Ethereal plane once per day. (FF)

Glossary

MM = Monster Manual PH = Planar Handbook MoF = Monsters of Fearûn FF = Fiend Folio U = Underdark WoSQ = War of the Spider Queen series

I should have more, and older AD&D references, but this will do for now I reckon.