Kuuderes often speak in a calm monotone and seem unaffected by the world around them. They never seem to be overly happy, excited, or surprised—just as they never appear sad, annoyed, or angry. Extreme examples may even seem to be completely emotionless.
Haru-can from Free! a good example.
The “dan” in dandere comes from the Japanese word “danmari” (黙り) meaning silence. Thus a dandere is a quiet and often antisocial character.
Danderes often want to be sociable but are too scared or too embarrassed to talk. They tend to fear that saying the wrong thing might get them into trouble—or some other socially awkward situation—so they say nothing to be on the safe side.
Of course, once danderes are befriended, they tend to lose their social inhibitions and become rather cute and happy—especially with the ones they love.
Dandere characters include the following:
Yuki Nagato (The Disappearance of Haruhi Suzumiya)
Hyuuga Hinata (Naruto)
Fuuka Yamagishi (Persona 3)
Elize Lutus (Tales of Xillia) - See more at:
http://www.mangago.me/home/mangalist/67089/#sthash.Y4HBNRYI.dpuf 
Tanaka-kun Wa Itsumo Kedaruge