What started a short list became quite a big description, more details inside the post.
Split.js is a lightweight, unopinionated utility for creating adjustable split views or panes.
Apipie- Rails DSL and API documentation lib. Allows to specify validation, versioning etc.
Segment - a little JavaScript class (without dependencies) to draw and animate SVG path strokes.
Let's Encrypt is Trusted now. Cool, a step further to free SSL certificates for everyone.
PgBarman - PostgreSQL backup tool. Hot backups, point in time recovery and many other features.