The version numbering is a little odd sometimes. I can't remember the exact names of all of them as they are mentioned in the Game Options dialog box...
Sid Meier's Civilization II v1.00 (I think mine was 1.05 or something, there must have been updates every now and then, with newer "printings" of the game being released as the latest available version)
--> Upgraded to v2.42 with the patch
Sid Meier's Civilization Scenarios: Conflicts in Civilization v2.62 [add-on]
Had a bunch of Microprose-made scenarios and some "bestonet" scenarios. Added events support.
--> CiC patch only updates some text/graphics/scenario files. Executable version is still the same.
Civilization II Fantastic Worlds: Scenarios and Construction Kit v2.7.8l (or something, commonly referred to as 2.78. Also note how the "Sid Meier's" prefix dropped off the box here) [add-on]
Added more scenarios, the scenario editor and more events.
--> No patch
Civilization II Multiplayer (version whatever) [add-on]
Civilization II Multiplayer Gold Edition [stand-alone, includes scenarios from CiC and FW]
Ultimate Civilization II Classic Collection [stand-alone, includes scenarios from CiC and FW]
The Multiplayer add-on was only available in Europe, I think, or maybe just everywhere except the US. UCC was the UK/EU version of MGE, I believe. MGE was also a Mac release of Civ2. Not sure if there was an earlier non-multiplayer Mac version of Civ2. The Mac version had one patch, v1.01 or something. The Windows versions had 2 or 3 patches, can't remember. At least v1.2 and v1.3. The v1.3 is the final patch in any case. As downloads there's one patch for the add-on and one common patch for all the stand-alone versions.
I believe the game options dialog says something like v5.4.0f?
Civilization II Test of Time v1.0
--> patch updates to v1.1
That's all of the versions of Civilization II there are. Well, the Windows versions in any case. I'm a bit iffy on the Mac versions. And then there are also Civilization II for the Playstation I and for N-Gage (or hasn't that been released yet?). I think those are about the equivalent of "Classic" Civilization II. Anyone know of any more?
Oh, and that list's in chronological order. Classic and CiC are from 1996, FW from 1997, MGE etc. from 1998 and ToT from 1999.