I'm not 100% sure how legit this link is by Otogi, but http://www.giantitp.com/forums/showthread.php?100736-3-5-List-of-Half-Breeds has a list of all the half breeds. The link also tells you what book this information would be in as well so all of it can possibly be confirmed.
It appears you can do Dwarf, Ogre, Beholder, and unless I'm mistaken Kender are essentially just the Dragonlance/Krynn version of halflings.
Base
Half-Ogres (Human/Ogre) - Races of Destiny, Savage Species, Bastards & Bloodlines
Decatuar (Elf/Centaur) - Bastards & Bloodlines
Muls (Human/Dwarf) - Dark Sun 3.5
Feytouched (Humanoid/Half-Fey) - Fiend Folio
Half-Bugbear (Elf/Bugbear) - Bastards & Bloodlines
Lasher (Dwarf/Roper) - Bastards & Bloodlines
Lurker (Gnome/Cloaker) - Bastards & Bloodlines
Spring Child (Humanoid/Dryad) - Bastards & Bloodlines
Trixie (Gnome/Pixie) - Bastards & Bloodlines
Watcher (Dwarf/Gargoyle) - Bastards & Bloodlines
Wendigo (Dwarf/Frost Wolf) - Bastards & Bloodlines
Wretch (Orc/Hag) - Bastards & Bloodlines
Wyrd (Elf/Ogre Mage) - Bastards & Bloodlines
Zenthyir (Human/Half-Lawful?) - Monster Manual II
Maeluth (Dwarf/Devil) - Fiend Folio
Half-Kender (Human/Kender) - Dragonlance Campaign Setting
Template
Half-Dragons (Anything/Dragon) - Monster Manual
Half-Fey (Anything/Fey) - Fiend Folio
Half-Rakshasa (Anything/Rakshasa) - Dragon Magazine, Bastards & Bloodlines
Half-Beholder (Anything/Beholder) - Bastards & Bloodlines
Someone let me know if I shouldn't have copied the info from the link over or if I should only have brought the relevant info over.
Muls (Human/Dwarf) - Dark Sun 3.5
Half-Ogres (Human/Ogre) - Races of Destiny, Savage Species, Bastards & Bloodlines
Half-Beholder (Anything/Beholder) - Bastards & Bloodlines
Half-Kender (Human/Kender) - Dragonlance Campaign Setting
