Hi Mark,
I'm not sure if this is readily available in the market, I have only seen home made ones so far.
A line pre tensioner to assist in spooling empty reels with new line, something simple and basic (cheap).
Another thought was a tool to assist in tying knots, maybe something that could hold one tag end while winding or twisting the other?
Or even something to assist in picking up Squid by hand to divert the ink squirt away from the user.
Any way, just a few thoughts that probably won't amount to anything.
Cheers
Choicebro