Riddle: I always have one eye open. What am I?
Answer: A needle
What Am I Riddles: I always have one eye open.
What am I? Riddle Meme.
Riddle: I am the ruler of shovels, I have a double. I am as thin as a knife, I have a wife. What am I?
Answer: The King of Spades (from a deck of cards).
Riddle: I am a path situated between high natural masses. Remove my first letter and you have a path situated between man-made masses. What am I?
Answer: A Valley. 
I am a path situated between high natural masses. Remove my first letter and you have a path situated between man-made masses.
What am I? Riddle Meme.
Riddle: I am served at a table, In gatherings of two or four; Served small, white and round. You'll love some, And that's part of the fun. What am I?
Answer: Ping Pong Balls.
Riddle: Lighter than what I am made of, More of me is hidden Than is seen. What am I?
Answer: An iceberg.
Lighter than what I am made of, More of me is hidden Than is seen. What am I? Riddle Meme.
Riddle: The things I bite, they don't bleed, I don't bite until you push me; I bring my victims together each time I bite, But they'll come undone if you pull it just right. What am I?
Answer: A Stapler.
Riddle: They fill me up and you empty me, almost everyday; if you raise my arm, I work the opposite way. What am I?
Answer: A mailbox.
They fill me up and you empty me, almost everyday; if you raise my arm, I work the opposite way. What am I? Riddle Meme.
Riddle: I'm like a doll, But I'm not for playing; I stand up straight, but if windy I may be laying; I'm well-known and famous for having no brain; I work outside both day and night in sunshine or in rain. What am I?
Answer: A Scarecrow.
Riddle: The more there is the less you see. What is it?
Answer: Fog.
Riddle: You can't see me, but I can see you; To be more specific, I see through. What am I?
Answer: An X-Ray.