On the A320,
MAX CLB GRADIENT SPEED = G.DOT varies from 205 kt at 60 t to 225 kt at 70 t ➔ + 2 kt/1 t
MAX V/S CLIMB SPD with ALL ENG OPERATIVE ≅ CLOSE TO TURB SPD varies from 279 kt at FL100 to 260 kt at FL250 ➔ - 1.3 kt/1000 ft
That is as close as you get to Vx and Vy etc.