I have six of the metal retractable bobbins that my father in law gave me...can't remember the manufacturer. Something nordic I think. I also have a bunch of other ones. I don't think I have any ceramic, I use what I have or what you'll send me.
I have about a dozen , but only four of them get regular use . I use one for wire , another for floss , and I have two Nor-vise bobbins for thread as I`ll sometimes use two different color threads on a single fly .
I am new into fly tying about 2 months now and I was just thinking about this last night. I have 2 at the moment - one is the nor-vise bobbin and it's great now that I'm getting use to it. The other one is from my kit.
I would like to have a 3rd bobbin immediatly soon and that should do me for a whuile.
Approx 6 or 8, a variety of brands, most but not all ceramic, most standard size with a few smaller for small Pearsall's spools. I use them for a wide variety of threads. I wrap all floss (silk) and wire by hand without a bobbin.
It definitely makes life easier than changing spools all the time.
About a doz each with diffrent colors and sizes of thread.
Most are not ceramic and one is the SM that I used to hate and almost a few years ago threw out but now love for heavier threads so I am glad I did not get rid of it.