In the earlier days of the Internet you were basically limited to three TLDs; .com (Commercial), .net (Network), and .org (Organization). Over the last decade+ there are now hundreds of TLDs (i.e. .biz, .us, .dev, .xyz, etc.) giving you many more options to choose from. While .com is (and always will be) the most popular, you are welcome to search for the TLD/gTLD that works best for you.