Game of Tribulation - 1974 - New/Sealed
Nominally the game is for 1-6 players, although the upper bound is arbitrary and the rules say nothing about how the game might be played solo. Possible solo challenges involve seeing how many tokens you can claim in a set time (e.g. 10 minutes total) or how many tokens you can claim racing against a countdown timer (e.g. 5-10 seconds per token).