There is no stated rule about choosing a particular domain name for a particular type of site. Use of .NET is generally, but not limited to, companies providing network infrastructure/services. A .COM domain is not limited to any particular type of website, it’s almost universal in nature and has highest recall value among internet users. Definitely, getting a .COM domain is very good, if one is available that you are searching for.
The best alternative to a .COM domain are gTLDs. Generic TLDs (gTLDS) are newly introduced domains that perfectly describes the type/category of a site. Examples are .photos, .recipes, .guide, .software, etc. These domains also improve SEO value of a website and help featuring high in search engine results.
To learn more, read Advantages of New gTLDs https://blog.znetlive.com/new-gtlds-invest-in-the-right-domain-name-for-your-business-and-website/