million-dollar
unrepeatable
specific
one and only
uniquely
unambiguously
first-of-its-kind
snowflake
one-off
rara avis
rare bird
like no other
ultradistinct
antrin
hellacious
specialism
self
apart
remarkable
superspecial
extraordinary
peculiarsome
non-imitation
singular
geason
similitude
unaccustomed
fremd
weird
alone
unequaled
distinctify
unique
queer as a clockwork orange
unparalleled
unequalled
out of the common
idiosyncratic
sole
unusual
custom-made
all that and a bag of chips
quaint
exotic
oddly
one-of-a-kind
speshul
spesh
peculiar
rare as hen's teeth