NP-Complete Static Square Puzzles In order to empirically test some CSP algorithms, I would like to compile a list of NP-Complete static board games. By static, I mean that a solution of the puzzle is simply an assignment of values to each entry of the board, in such a way that the rules of the games are satisfied. 

For instance, slitherlink,numberlink, sudoku, filomino, kakuro etc, are the types of puzzles I'm looking for. 

Preferentially, the puzzles should satisfy the following conditions: 


Scalability: The puzzle can be defined for $n\times n$ boards for each
$n$. Or if this is not possible, for each $f(n)$ where $f:{\bf N}\rightarrow {\bf N}$ is some 
easy looking function. 
An online library of instances for the puzzle should be available.  


What would be online databases for such puzzles? For instance, the section Games and Puzzles of this wikipedia page has many square games satisfying condition 1. So what I'm really looking for is a of puzzles that also satisfy condition 2. 

Please feel free to suggest more than one puzzle in one answer.
Two such puzzles that I know about are:

Unruly. This website has an online library of puzzles and solutions and a generator for puzzles of arbitrary size.
Masyu. This website has a library of puzzles and solutions. It also links to several variants of the puzzle.

Actually, the page where the Unruly puzzle is found lists more such puzzles, some of which satisfy your conditions, while others don't.