I remember going to a gig many years ago and the bass player (Pete Way I think) had a rig that included a brightly illuminated tuner, up on the stack somewhere, which was going throughout the set as he played, really big and clear that you could "read" from the audience / mosh pit/ whatever.
Funnily enough it is the thing that sticks in my mind about the gig, no idea what make or model it was, but v. handy I thought 😁