Logidze: Log Database Changes in Rails Apps — Logs are stored in the database in a JSONB column (so Postgres only). It claims to be faster than Audited and PaperTrail which both remain fine alternatives in this area.
Blind Index: Securely Search Encrypted Database Fields — Works with Lockbox and attr_encrypted.
The tool to find inconsistency between models schema and database constraints.
A library for bulk insertion of data into your database using ActiveRecord.