typelevel/cats-effect

The IO monad for Scala

propensive/magnolia

Simple, fast, debuggable generic derivation for typeclasses

djspiewak/shims

Seamless interop layer between cats and scalaz

xuwei-k/play2scalaz

Scalaz typeclasses <~> Playframework2 typeclasses

softwaremill/scala-common

Tiny independent libraries with a single purpose, often a single class

mlopes/wen

Date and time types and instances

scalaz/scalaz-deriving

Principled, fast, typeclass derivation.

hablapps/puretest

Purely functional testing in Scala