What started a short list became quite a big description, more details inside the post.
Best Practices for Building a Microservice Architecture. Looks like a wide set of questions covered.
Using Elementary OS 0.3 Freya daily build for two days. Not ideally stable (it is not even beta), but beautiful :) Btw. Beta status could be tracked in http://isfreyareleasedyet.com/.
Runnable.com - jsFiddle alternative for server side (PHP, Ruby, Bash and even much more) languanges. Allows to run, share and collaborate on code snippets.
bouncejs allows to make nice CSS3 animations composition via GUI
vtop - Node.js based htop replacement. Looks very nice, but I dont think I will use it on real server.
Cool JSON Editor. Could be usefull for some optional settings configuration or something.