Airframe is an authorization library ala Bodyguard for use in your contexts.
You write Policies. A Policy authorizes (and narrows the scope of) subjects and actions.
HTTP Client for EventStore (geteventstore.com)
M-Bus & Wireless M-Bus (wM-bus) parser library
Interval/range operations on Decimal, DateTime, Integer, Float, etc. Ecto support for Postgres range types like int4range, daterange, tstzrange, etc. Implement intervals over your own custom data.
A utility to increase ergonomics when working with Keyword lists.