If you are starting to work on the new web project there is huge amount of tools and services available that may speed up your development, improve code quality, simplify maintenance and deployment etc.
Let's split such tools by group for future reference. Most of the tools are agnostic to your environment. Some of them may be not. I used a lot of them in the Node.js and Clojure projects.
This list is just trivial attempt to organize popular tools and services you might need developing your modern application.