These are the different possibilities of how games can be released together.
- Compilation random
This is the usual case. Two or more random stand-alone games are released as a collection which is marketed as such with its own name. Example: Gold Games 2. - Compilation series
Two or more stand-alone games from a series (direct sequels) are bundled together, and marketed as such with its own name. Example: Diablo Battle Chest. - Compilation franchise
Two or more stand-alone games from a franchise (no sequels) are bundled together, and marketed as such with its own name. Example: Final Fantasy Anthology. - Compilation game and add-ons
One game is re-released bundled with all or some of its [significant] add-ons, and marketed as such with its own name. Example: Final Fantasy XI: Vana'diel Collection 2008. - Original release with bonus games included
This is the case for new game releases that include bonus games or add-ons, for instance a sequel containing the first game as a bonus. The package is marketed as the game newly released. - Original release with bonus games integrated
This is like Case 5, only that the bonus game(s) are integrated into the gameplay of the newly released game. Example: Day of the Tentacle, which contains Maniac Mansion on a computer inside the game. - Re-Release with bonus games included
This is also like Case 5, only that it's a re-release of a game with bonus game(s) (mostly add-ons) included that the original release had not in. - DLC Release
This is actually a Case 4, but is separate here to distinguish between the real Case 4 examples and this DLC plague that haunts us for some years now. - Covermount
This is the case for CDs / DVDs mounted on the cover of a gaming magazine. - Promotional material included
This case is for releases which contain promotional versions of other games (i.e. demos).