For most businesses, a .com domain is the clear best choice. For specific countries, having a country code TLD as well can avoid confusion (is it .com or .co.u

For most businesses, a .com domain is the clear best choice. For specific countries, having a country code TLD as well can avoid confusion (is it .com or .co.uk? Both/either!) and increase confidence of local support and/or regulatory compliance. .io can work for API-based service businesses, or (oddly) games. .net can work for ISPs, Telcos, etc, although generally again in tandem with the .com. The rest of the TLD explosion is basically a scam, predicated on companies buying the MyCo.<whatever> domain to try to avoid customer confusion, trademark dilution, negative publicity, etc. Just spend the money on the .com if you have to, or make sure you pick a company name that has an available .com and social media accounts. It's easily worth it to lock in the right name.