Chess Opening Database - Shredder Chess

Encyclopaedia of Chess Openings BI

The Ultimate Guide to Chess Openings

ChessX Flathub

We made a tool that lets you search the lichess game database by chess concepts. Link in the comments : r/chess

Master Chess Openings, Chess Wiki

Does the win/draw/loss rate from the opening database also apply to lower rated games? - Chess Forums

How do I use the Game Explorer? - Chess.com Member Support and FAQs

ChessBase Opening Encyclopedia 2017

How To Use The Opening Explorer - by Nate Solon

The Unacceptable Flaw with : Use of Game Explorer/DB in Vote/Turn Chess - Chess Forums