Chess Openings Trainer by Piero Toffanin

Daniel Fernandez: Weapons against the Caro Kann - Vol. 1 & Vol. 2

Openings trainer - Chess Forums

Chess Openings Trainer on the App Store

Chess Openings Trainer by Jake Pitman

FRITZ TRAINER - Basic Opening Strategy

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

GitHub - mirkootter/chess-trainer: Very simple chess opening trainer (currently only stafford gambit)

Chess Openings Trainer

Dvoretsky: World's Best Chess Trainer - Forward Chess

Chess Chess TRainer