typelevel/cats

Lightweight, modular, and extensible library for functional programming.

scalaz/scalaz

Principled Functional Programming in Scala

scala-native/scala-native

Your favorite language gets closer to bare metal.

milessabin/shapeless

Generic programming for Scala

typelevel/scalacheck

Property-based testing for Scala

fthomas/refined

Refinement types for Scala

scopt/scopt

command line options parsing for Scala

scalapb/scalapb

Protocol buffer compiler for Scala.

scalatest/scalatest

A testing tool for Scala and Java developers

scalameta/scalameta

Library to read, analyze, transform and generate Scala programs

scalalandio/chimney

Scala library for boilerplate-free, type-safe data transformations

typelevel/simulacrum

First class syntax support for type classes in Scala

typelevel/squants

The Scala API for Quantities, Units of Measure and Dimensional Analysis

com-lihaoyi/fastparse

Writing Fast Parsers Fast in Scala

softwaremill/quicklens

Modify deeply nested case class fields

com-lihaoyi/scalatags

ScalaTags is a small XML/HTML construction library for Scala.

softwaremill/magnolia

Easy, fast, transparent generic derivation of typeclass instances

scallop/scallop

a simple Scala CLI parsing library

scala/scala-parser-combinators

simple combinator-based parsing for Scala. formerly part of the Scala standard library, now a separate community-maintained module

com-lihaoyi/os-lib

OS-Lib is a simple, flexible, high-performance Scala interface to common OS filesystem and subprocess APIs