Here is a list of where most of the unused examples should go (I think the only one I couldn't place was someone's vague mention of the Pink Panther theme):
Aquaria does this. There are at least five "different" tracks on the soundtrack that are slight variations on a basic (gorgeous) theme, and two or three really different tracks that still work in elements. There's one particular motif which is worked into so many of the songs because it has gameplay significance.
Donkey Kong Country 2 has the title theme developed into the boss theme, Klubba's theme, and the theme for levels atop ship rigging.
Final Fantasy series composer Nobuo Uematsu seems to do this to a subtle extent in some of the games. You can hear some recurring tunes in Final Fantasy IV (such as the tune that's most notably used for allies joining your team), but it's more prominent in Final Fantasy V, Final Fantasy VI (where the main theme of the game is basically also Terra's leitmotif, and Final Fantasy VII (which literally has a soundtrack entry called the "Main Theme"; if you don't know what I mean, try singing "do re mi ti la").
Final Fantasy X: Three main themes (To Zanarkand, Suteki da Ne, and Sight of Spira) that are reheard multiple times, culminating in the awesome credits music.
Final Fantasy Tactics Advance may be another example but this troper hasn't sorted through the soundtrack yet. The tune in question is "so, so, so, mi fa so, ^do, (b)ti, (b)la, so" etc..
Stratos 4 has a number of tracks, including one labeled "Mikaze's Theme" (for the lead main character), that all share a tune. At the last episode, this is revealed to be the tune of the second ending theme (which is used for the ends of whole seasons).
Rareware uses different songs for the levels in their games, but the songs take on different motifs when you travel to other portions of the level. It's most noticable in Banjo-Kazooie and Donkey Kong 64:
If there is an underwater segment, the music will be played softly, with pianos and xylophones.
If there is a cave, it will be played slowly, with a xylophone and lots of echo.
During a boss fight, it will be played loudly by an orchestra. Expect loud trumpets.
Here is the discussion of the other YKTTW: https://tvtropes.org/pmwiki/discussion.php?id=85ed73kw9e33xdpi1e1aktzc&trope=DiscardedYKTTW
Here is a list of where most of the unused examples should go (I think the only one I couldn't place was someone's vague mention of the Pink Panther theme):
Recurring Riff examples
Variable Mix examples:
Theme and Variations examples:
Note: If the examples were already there, they were not copied from here.
Edited by GlennMagusHarvey