The dwarf in 'Snow White and Rose Red'
Goblins in 'The Princess and the Goblin', by George MacDonald, if my memory serves me correctly.
The wee folk in changeling tales.
The tale where the brother searches for his two elder brothers, and finds them enchanted by a dwarf - can't remember the name.
The tale where the stunted troll keeps his heart in a fingerbone in a tree, and the hero has to find it and break it to free the princess imprisoned by the troll - again can't remember the name.
The fairies in old folklore can be very malicious, and at the very least are credited with stealing cattle and causing (often fatal) illnesses. Dwarves and goblins are generally not nice to know, as are trolls, who can be very short in some tales. Imps are also usually bad for people, like Tom Tit Tot (an English version of Rumplestiltskin).
Bogles also come to mind, again from folklore.
The Elf King in the Oz series (the one who was afraid of eggs)