Here are some infrastructure tools for the Scala community I (co-)authored and maintain:
Sbt Plugins
sbt-dependency-graph
An sbt plugin to analyze the external dependencies of an sbt project. It was originally created out of the need to help a customer which had grown quite a codebase and needed to understand what they were actually depending on.
sbt-revolver
A developer productivity sbt plugin which allows to run and recompile services in the background.
sbt-optimizer
sbt-optimizer is an experimental plugin that hooks into sbt's execution engine and provides a visualization of task run times. This allows to troubleshoot performance problems in sbt like bad execution performance for large multi-module projects.
sbt-boilerplate
An sbt plugin to create boilerplate Scala code from templates. Used in spray, akka and other libraries.
Release Train Reports for new Scala Releases
For binary incompatible Scala releases it always takes some time until the essential libraries are updated to the latest version.
The release train script watches public repositories for new artifacts for new Scala versions and publishes a new report to a gist every day. The report lists published and missing artifacts and shows which libraries need to be released to remove blocks for depending libraries.