Searching for character musical themes with alternate versions

[Bill Nye 924]

Pretty much like the title says, I'm looking for audio to use in my roll20 campaign for very important npcs. Naturally it'd be difficult to do it for every npc, so only doing it for specific ones.

What I'm looking for is orchestral, or at least non-lyrical, audio that has multiple versions, like a normal version and a sad version. Most of these aren't characters I expect to survive forever, so I'm looking for sad versions of their themes for when that comes.

[MageHunter]

I would take a look at the Undertale soundtrack. It has a lot of repetition across songs, though with clear differences.