Matching: MatchingWise
Combinators: CombinatorsCowan
Conditional procedures: ConditionalProceduresSamizdat
cond guards: SRFI 61
Lambda*:
Void: VoidCowan
Named parameters: NamedParametersCowan or SRFI 89
and-let*: SRFI 2
Generalized set!: SRFI 17
receive: SRFI 8
rec: SRFI 31
Cut/cute: SRFI 26
Loops: SRFI 42 or Riastradh's foof-loop or Chibi loop
Generic accessors/mutators: SRFI 123