Happily, they're super easy (and inexpensive) to make yourself, which I discussed here a while back. So you can have a whole bunch of them to fit every whim, every season, every holiday, every project. They're so simple to make they really don't require a tutorial. Basic instruction: Glue one of a pair of magnets to the back of something. Boom. Needle minder. That's it.
However, since I was making a few more today, I decided to snap a few pictures to share ideas for what items you can use to make them, how to make those items usable, and how to store them. Here are the ones I made today, in about 30 minutes (easy!).
You can use all kinds of things to make needle minders. Here we have a kitty charm (Jo-Ann's), a Christmas tree brooch (Hobby Lobby), and some buttons (Hobby Lobby & Jo-Ann's).
A button shank remover is a great little tool to have on hand. The curved blades allow a close cut so the back of the button is flat.
Old jewelry from your jewelry box or inexpensive costume jewelry makes great needle minders. Pins can be easily twisted off with a pair of pliers (don't stick yourself!).
When using charms, sometimes you can get the charm loop off cleanly with pliers, but more often than not, trying to remove it will either damage the charm or leave little points of metal behind that are too small to be removed. My solution is to just cover the charm loop with a small crystal. These crystals (Hobby Lobby) came in a package that contains multiple sizes, which is great because you don't have to guess what size you need and only buy one size. I use strong craft glue to attach these, as I've found that the chemicals in super glue eat away the backing on the crystal and leave it dull-looking.
These are the super strong magnets I use (left, 6.3 mm from Michael's; right, 8 mm from Hobby Lobby). I prefer the smaller 6.3 mm size, but either will do. Use caution with these, they are very strong. You can use super glue to attach them, but hot glue usually works just as well for me.
I store my collection in a little metal pencil case. Very compact and tidy.
A combination of purchased and homemade, I've used old jewelry, charms, pendants... even a metal badge from a festival we went to. The little black one with the flowers painted on it is the first needle minder I ever got. I've had it for more than 20 years--way before needle minders became a "thing".
And that's all there is to it. Very easy. Very inexpensive. And they make really cute little gifts for fellow stitchers (Christmas is coming!).