Well, in book one Professor Quirrell tried to kill Harry. In book two, the basilisk tried to kill Harry. In book four Barty Crouch Jr. disguised as Mad-Eye Moody tried to kill Harry.
And book seven spoilers (DON'T HOVER OR HIGHLIGHT IF YOU DON'T WANT TO KNOW):
In book seven Vincent Crabbe attempts to kill Harry with Avada Kedavra at the end of the book in the Room of Requirement chapter.
These examples are attempts on Harry's life on behalf of Voldemort, but other individuals are carrying out the deeds.
ETA: One might argue that Dobby also attempted to kill Harry throughout book two ;)
ETA 2: Aragog's sons and daughters tried to kill Harry and Ron in book two. The Whomping Willow might have managed it, but we don't know its intentions, again in book two. I believe in book five, Harry, Ron, and Hermione almost were shot with arrows by the centaur herd (going off the top of my head on that one). Professor Lupin, as a werewolf, came after Hermione and Harry in book three. A Dementor almost killed Harry in book three by causing him to pass out in the sky and fall over 100 feet down to the Quidditch pitch; however, Dumbledore saved Harry with Arresto Momentum. If I think of any more, I'll edit them in. :)