IMO the coolest bass gadget ever is. . . the chromatic tuner.
I started out at a time when you either had a tuning fork, pitch pipes or you had to tune up to a trumpet, if you had a brass section, or an organ. Trying to stop the others making a noise when you needed to tune up was a nightmare. And forget it in a noisy night club. I just don't know how we managed to get a whole band in tune back then!
Silent tuning is a wonderful evolution.