Browsing for Combat Mechanics

Is there a good place where one can quickly browse different types of combat resolution mechanics?
It's hard to search for this and get a good wheat-to-chaff ratio.

I'm particularly interested in browsing simpler style mechanics that would apply unit vs. unit.
As an example of the kinds of things I'm looking for:

1) Unit combat strength expressed as a single number. Higher number always wins.

2) Unit combat strength expressed as 2 numbers, offense and defense. Compare each units offense to the others' defenders. If an offensive score is equal or greater, that unit eliminates the other. Compare scores simultaneously.

3) Unit combat strength expressed as 2 numbers, offense and defense. Roll die and add offensive value, if total is greater then defender value, then score a hit. Alternate attacks, unit that runs out of hit points first loses.

4) Unit combat strength expressed as a single number. Find the difference between the two scores. Select a particular die according to that number. Roll die, results are printed on die.

5) etc...