unprecedented
alone
exceptional
extraordinary
fabulous
indescribable
ineffable
legendary
lone
marvelous
mythical
noteworthy
phenomenal
portentous
prodigious
remarkable
singular
sole
solitary
solo
stupefying
stupendous
unique
unparalleled
unrepeatable
unspeakable
wonderful
incomparable
inconceivable
inexpressible
superhuman
transcendent
unbearable
unbelievable
unbounded
uncommon
unequalled
unheard-of
unmerited
unsurpassed
untold
unwonted
utmost