Apple offers several strap options included with their watches, some depending on the model purchased. The most common band options, often included with new Apple Watches, like Series 9, are the Sport Band and Sport Loop, available in several colors such as Midnight, Starlight, White, Red, Pink, etc.
Other group options include the Ocean Band, Alpine Loop, Milanese Loop, Trail Loop, Solo Loop, Braided Solo Loop, and more. Apple and other retailers also offer tons of bands made from different materials in a multitude of colors and designs.