[@Slime]Mixed Bloods don't appear much in Fate, but are more prominent in other TM works like Tsukihime and Kara no Kyoukai. The only one I can remember from Fate is Natalia Kaminski, Kiritsugu's mentor, who was half Succubus. The notable ones in the Nasuverse are the Tohno and Kishima, who possess Oni Blood.

Akiha can 'plunder' the lifeforce of other creatures, and Kouma...well he's just ridiculous strong. Like crush a tree with your bare hands strong. 

Aldrych's Faerie blood grants him 'Faerie Speech' allowing him to communicate with nature. It also grants other abilities, like heightened speed and healing, and weaknesses like being unable to touch cold iron or lie. Things typically associated with Faeries.