As far as I know:
Getters/setters related:
apply
update
identifier_=
Pattern matching:
unapply
unapplySeq
For-comprehensions:
map
flatMap
filter
withFilter
foreach
Prefixed operators:
unary_+
unary_-
unary_!
unary_~
Beyond that, any implicit from A to B. Scala will also convert A <op>= B into A = A <op> B, if the former operator isn’t defined, “op” is not alphanumeric, and <op>= isn’t !=, ==, <= or >=.
And I don’t believe there’s any single place where all of Scala’s syntactic sugars are listed.