They are made from metals to wood. My best advise in not to use the small metal ones from craft stores. Not only will you find that they tend to loosen but the rollers often do not fit right in some cases. If you drop beads on the rug or floor. Put a nylon over the hose of your vacuum, hold the nylon so it will no get sucked up into the vacuum.
Cats love to chew on the threads and dogs love to chew on wood.
There are several type of seed beads on the market. The kind you use depends on how you want you project to look. Beads come in many forms and sizes, Here are a few of them. Small glass beads which look like little seeds. They are sized according to number, the higher the number, and are available in a variety of finishes and a number of shapes.