Baseball Pitching Velocity Suggestions/Exercises?

Any baseball pitchers with suggestions or exercises for improving their throwing velocity? I pitch in a men's wooden bat league in New York City as a knuckleballer since my arm strength has fallen due to injury and "tenure". My changeups are now my fastball and slider to keep batters honest 10% of the time. I usually get the best control when I throw my knuckleball slower, with late drop, but I want to gain velocity to have a few different speeds/actions to play with.

...I've had some UCL and shoulder strains in the past before I converted to knuckleballs, but perhaps I can turn back the clock with some of your tips.

Here's my typical knuckleball grip. Would be curious to hear if you have another reliable way.

Thanks!