Use The Index, Luke! : A tutorial covering SQL indexing and SQL tuning for developers: avoiding unnecessary details about database internals.
SQL indexing is the most effect...
MySQLTuner : MySQLTuner is a script written in Perl that will assist you with your MySQL configuration and make recommendations for increased performance and stabi...
WebPagetest : Run a free website speed test from multiple locations around the globe using real browsers (IE and Chrome) and at real consumer connection speeds.
New Relic : New Relic’s SaaS-based Application Performance Monitoring helps you build, deploy, and maintain great web software.
Also, server monitoring, and more.
SPOFCheck : A CLI tool for detecting frontend SPOF, mainly blocking scripts and CSS
Vitess is a database clustering system for horizontal scaling of MySQL.