Example:
Person A: I won't vote for the lesser of two evils.<p>Person B: But if lots of people like you did that in this election, the greater of two evils might win.<p>I thought this was the bandwagon fallacy, but yourlogicalfallacyis.com/bandwagon describes the fallacy as "appealing to popularity or the fact that many people do something as an attempted form of validation." In this case, refusing to vote for the lesser of two evils is <i>unpopular</i>. Other websites have similar definitions of the bandwagon fallacy.
Nirvana or perfect solution fallacy are at least related. Basically they’re saying they won’t take part because there isn’t a “perfect candidate” when that’s not a likely option in particular because you can use that excuse with any pairing.