Redone - Select One game mechanic and find three games the use it

This was a hard decision to choose one game mechanic but I have made a decision on using the core game mechanic:
                                Collecting
I have chosen this game mechanic because it is easy to expand on and has so much potential from this starting point. I can expand off into so many different areas and intertwine many other mechanic with this one.

Three games that use this mechanic are:
-Age of Empires II
-Super Mario Bro's
-Call of Duty - Black Ops II

Age of Empires II: This game uses collection as a core mechanic because the main goal of the game is to collect as many resources to gain a stronger army and build the ultimate base to defeat the enemy.

Super Mario Bro's: This game uses collection from collecting coins that could potentially give you lives. If you collect 100 coins you gain a life. Which leads me to collecting lives as well which can be gain by orange mushrooms/coins. The aim of this game is to collect the coins that are scattered around for Mario to collect.

Call of Duty - Black Ops II: I put Black Ops in this category because it's a game where you can collect multiple things such as all kinds of weaponry that you can unlock, achievements, emblems, calling cards and even camo to put on your gun. 


Add on for lolz:
Many more collection games may include:
Multiple shooting games such as : All the halos, all the C.O.D's, Battlefield, Dead space.
Many games have this mechanic because it is vital in most games to complete levels or pass missions. You could even expand collection to collecting medals and achievements.