phpMyAdmin - phpMyAdmin is a tool written in PHP intended to handle the administration of MySQL over the Web.
Adminer - Adminer (formerly phpMinAdmin) is a full-featured database management tool written in PHP.
Valentina Studio - FREE native database manager for SQLite, MySQL, PostgreSQL, SQL Server and Valentina DB.
DBeaver - DBeaver - Universal Database Manager and SQL Client.
SQLite Manager - Manage all your SQLite databases using this lightweight extension for Firefox, Thunderbird...
HeidiSQL - HeidiSQL is a powerful and easy client for MySQL, MariaDB, Microsoft SQL Server and PostgreSQL. Open source and entirely free to use.