Chesstempo.com now has an opening trainer : r/chess

Best Chess Openings for White: Full Guide - 365Chess

A Complete Guide On Tempo In Chess With Example!

ChessTempo User Guide

Is Chess Tempo performance really that important? It seems like the correlation between it and OTB playing strength is quite weak. : r/chess

chesstempo - Chess Club

The biggest chess databases - Chess Forums

Can someone explain to me how the chesstempo endgame trainer works? I'm losing points even when I easily get trivial positions like this one in 2 moves : r/chess

A Pawn is Worth Three Tempi - Chess Lecture - Volume 94 Chess DVD

Reached 365 days on r/chesstempo! Easy even if you usually leave standard puzzles overnight. No need 2nd account or griefing. Just do blitz on old site (old.chesstempo.com/chess-tactics.html) and standard on new site.

Chess Tactics Puzzle Training : Chesstempo.com Tactics and Puzzle Training review (Chessworld.net)