A diveboat in WPB lost track of my daughter and I when the float line broke, no boat in sight when we surfaced but not a panic situation because we could see the homes on the beach however they found us before I blew up the second sausage. In the Galapagos we lost a diver for an 1:44 and that’s another spot where government help was two days away.
I carry a really big sausage now, light for it, strobe light, mirror and a Platapus folding bike bottle, meant to go in a bicycle jersey back pocket. I put water in mine when I get to the resort and then it goes in the BC pocket.
My Jon line which is normally used to clip onto the anchor rode during safety stops can be used to tie divers together so you don’t drift apart.
Something you can add to your pocket and you may be able to pick one up free at work is a big yellow HazMat trash bag, when filled with air these are real easy to spot. One diver told me he hung a weight pouch on the tie straps that made the bag more managable and he floated better too.
I’m looking to buy a Nautilus Lifeline GPS soon, I can use that both for diving and sailing.