Use Cellianna's tiles, they're awesome.
If you want to get away from the chibi/1-tile high characters you'll have to draw some yourself though. There are char generators like this one: http://www.famitsu.com/freegame/tool/chibi/index1.html
But I can't find any that do normal proportioned characters. Time to draw them yourself :V (it's not too hard, by the way. There are tutorials on pixel art)
Oh, and I suggest you also do parallax mapping (making maps using photoshop/gimp) instead of the editor, you can do cool stuff like this:
(Left = just editor. Right = edited in Photoshop/GIMP)
http://i.imgur.com/vURGj8x.jpg
*Shameless self-promotion*
Obviously, it's to get away from the colourful/happy look of most of the tiles. Really depends on the game you're trying to make but for a horror game I would definitely suggest it since you can get the lighting and shadows exactly as you want for that spooky feeling