Here are some infrastructure tools for the Scala community I (co-)authored and maintain:
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.
A developer productivity sbt plugin which allows to run and recompile services in the background.
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.
An sbt plugin to create boilerplate Scala code from templates. Used in spray, akka and other libraries.