OMGChess: More on Learning Openings

Chess Position Trainer

Chess Openings Trainer Pro - Apps on Google Play

Chess Position Trainer Tutorial: Using Chess Engines

Chess Position Trainer - Lubbe Schach

Opening training with Fritz 17

Catastrophes & Tactics in the Chess Opening Workbook - Vol 1: Indian Defenses: Tactical puzzles to help exploit opportunities and avoid disasters in (Winning Quickly at Chess Workbook Series): Hansen, Carsten

Chess Openings Trainer Lite for Android - Download

I made an interactive trainer for learning the queens gambit opening, including 86 variations : r/chess

Fritz Trainer Software

Chess Opening Trainer App Price Intelligence by Qonversion