Collectable items are something that a lot of people take a lot of enjoyment in when playing open world games. Lots of little items that are hidden around the environment for the player to seek out and find. Some games can be quite generous and give you in game maps that will reveal the locations of the hidden items, others do not.
The interactive maps on this site are all based around filling in the gap where in game maps are not being provided. Collectable maps have game maps with markers to show you the location of all of the hidden items in the area that the map is representing.