There's Call of Chernobyl, which technically isn't standalone since it "requires" Call of Pripyat to be installed, except you can just disable the check it makes and play it anyway without CoP.
It combines the maps from all 3 games (taking the Clear Sky versions for ones which are present in both SoC and CS), plus some ones that were cut from SoC, and an original one made by the modders. It only has the maps however, not the actual story content of the games.
There's also a whole host of other mods which were developed from it, adding even more stuff (since CoC by itself is quite barren in terms of content, it was meant more as a base for other mods). Anomaly's the most popular one, but there's also a few others.
There's Call of Chernobyl, which technically isn't standalone since it "requires" Call of Pripyat to be installed, except you can just disable the check it makes and play it anyway without CoP.
It combines the maps from all 3 games (taking the Clear Sky versions for ones which are present in both SoC and CS), plus some ones that were cut from SoC, and an original one made by the modders. It only has the maps however, not the actual story content of the games.
There's also a whole host of other mods which were developed from it, adding even more stuff (since CoC by itself is quite barren in terms of content, it was meant more as a base for other mods). Anomaly's the most popular one, but there's also a few others.