This is going to hurt.... pre-1970s, most of the third parties weren't very good! Consider that I keep reluctantly voting Prohibition despite the fact that I think they're sticking their noses into other people's business... they're less bad than the alternatives (Socialist/Communist/What-have-you), especially come the thirties...
1900: Reluctantly Woolley/Metcalf (Prohibition). Less bad than Debs, at least...
1904: Don't know who they are, but since Holcomb/King (Continental) only received 830 votes, they're unlikely to, you know, win.
1908: Hisgen/Graves (Independence)
1912: Roosevelt/Johnson (Progressive)
1916: Reluctantly, Hanly/Ladrith (Prohibition)
1920: Macauley/Barnum (Single Tax), I might not like the 'single tax', but it'd only be one tax....
1924: Nations/Randall (American). Don't know enough about them to hate them..
1928: Yeouch.... Varney/Edgerton (Prohibition) seems least bad...
1932: Dunno if they're good or not, but the party name of the Harvey/Hemenway ticket (Liberty) sounds kewl...
1936: Again, reluctantly vote for Colvin/Watson (Prohibition)
1940: Again, " " Babson/Moorman (Prohibition) assuming Knutson (Independent) doesn't count as 3rd-party
1944: No Candidate (Texas Regulars)
1948: Very reluctantly, Thurmond/Wright (States' Rights)
1952: MacArthur/Byrd (Constitution)
1956: I have know idea what Krajewski/Yezo (American 3rd Party) stand for, but they sound kewl so I'll vote for 'em.
1960: Daly/Curtis (Tax Cut)
1964: Hensley/Hopkins (Universal) - total of 19 votes originally!
1968: reluctantly Munn/Fisher (Prohibition)
1972: Hospers/Nathan (Libertarian) - now we're talking!
1976: MacBride/Bergland(Libertarian)
1980: Clark/Koch (Libertarian)
1984: Bergland/Lewis (Libertarian)
1988: Paul/Marrou (Libertarian)
1992: Perot/Stockdale(We The People)
1996: Close one... Browne/Jorgensen (Libertarian) narrowly over Perot/Stockdale (Reform)
2000: Browne/Olivier (Libertarian)
2004: Also close... Badnarik/Campagna (Libertarian) over Peroutka/Baldwin (Constitution)
Weirdly, my top two third parties are Libertarian and Prohibition...
. Only times I would have actually voted third party would be perhaps 1960 (Daly), 1968 (though I'd have a write-in, say Reagan/LeMay or somesuch), 1972 (Hospers), maybe 1976 (tough choice between Ford and MacBride), maybe 1988 (Paul narrowly over Bush), and 1992 (Perot). Or 3 definites (68, 72, 92) and 3 maybes (60, 76, 88). Between 1900 and 1960, pretty much every 3rd party was worse than the Republicans, and most were worse than the Democrats. The only 'good' candidate would be TR in 1912, and I disagree with many of his policies.