The choice of the best domain extension after .com depends on your specific needs and goals. There are several domain extensions (also known as top-level domains or TLDs) to choose from, and the best one for you will vary based on your website's purpose, business and target audience.
If you are just looking for the next most used alternative or popular alternative then it must be .net
If your website is country specific and are willing to target audience of a specific country then there are domain extensions with country code TLDs like .us .co.uk, .ca, .au
org: Typically used by non-profit organizations.
.net: Originally meant for networking or internet-related websites, but now used for a wide range of purposes.
.co: Originally intended for Colombian websites but has gained global popularity and is often used as an alternative to .com. It is also considered for the company name.
.io: Originally intended for websites related to the British Indian Ocean Territory, but gained popularity among tech startups and tech-related websites.
.biz: Typically used for business or commercial websites.
The best domain extension after .com depends on the nature of your website. For global reach, consider .net or .org. If targeting a specific geographic location, country-specific extensions like .co.uk or .de may be suitable. Newer extensions like .io are popular for tech startups, while .app is ideal for mobile apps and software.
I have always believed that there is no "best" option. Sure, ideally you wold want a .com as this is what people know. In my opinion, weather you have a .net or a .info it comes down to marketing. Think about cPanel they have a .net, and are well branded
It's fully depends on your business model. If you are a tech company, you can use .io/.net, if you need regional clients you can use country specific domains, for artificial intelligence you can use .ai, for organisations you can use .org.