haystack

noun 0.661

diamond in the rough

noun 0.615

eye of a needle

noun 0.610

one in a million

noun 0.593

needle

noun 0.582

thread the needle

noun 0.557

tough nut to crack

noun 0.554

holy grail

noun 0.549

treasure hunt

noun 0.541

finding

noun 0.534

shot in the dark

noun 0.531

drop in the ocean

noun 0.529

rara avis

noun 0.529

rare

noun 0.525

wild-goose chase

noun 0.518

treasure trove

noun 0.511

egg hunt

noun 0.500