Sequel Pro Alternatives for Web

With phpMyAdmin you can manage MySQL and MariaDB via a user interface. phpMyAdmin is free and open-source portable web application written primarily in PHP. It supports wide range of native MySQL and MariaDB database operations including maniging tables, columns, relations, indexes, users, permissions and more.

Adminer provides administrators, developers and website maintainers with a full-featured database management tool written in PHP. With Adminer you can to a database servers with username and password. List fields, indexes, foreign keys and triggers of table. Change name, engine, collation, auto_increment and comment of table. Alter name, type, collation, comment and default values of columns. Create, alter and drop indexes, foreign keys, select form view and call stored procedures and functions. The software is distributed under the Apache License which makes it free and open-source. Adminer supports a wide variety of relational and NoSQL databases including MySQL, MariaDB, PostgreSQL, SQLite, MS SQL, Oracle, Firebird, SimpleDB, Elasticsearch and MongoDB.

DataRow is a web-based Amazon Redshift client with visual analysis and collaboration features for data analysts and data scientists.

dbForge Studio for MySQL is a universal GUI tool for MySQL and MariaDB database development, management, and administration. 

With pgRITA you can analyzes your database schema against common rules to easily adhere to best practises. pgRITA provides a interactive report that can be used to improve your PostgreSQL schema and minimize errors.