7 Wonders Duel: Pantheon
Buy this firstA BGG reviewer with 1,000+ base plays says it lifted the game to one of the best two-player games; a 2016 review calls it fun but not essential. r/7WondersDuel posters play it every time.
Needs: Just the base game
Adds: A Pantheon board with 16 deity powers, three Grand Temples that replace the Age III Guilds, two new Wonders and three Progress tokens.
Fixes: Adds a second action type (summoning a god instead of taking a card) and gives players more ways to change turn order and spend coins.