URL Auto-complete Suggestion
I had this idea but then I opened IE settings and found they had this idea before :D Anyway, it's a great idea. The idea is add an extra autocomplete option, one that would add a custom suffix, when pressing Ctrl+Shift+Enter. This is especially useful for people outside US, or 96% of the population. People living, for example, in Italy are always entering addresses ending with .com.it, people from UK are going to .co.uk, and with this option we would be able to autocomplete with our country default suffix. Vivaldi could use the default language as an option for default custom suffix on install. tl;dr Ctrl+Shift+Enter with custom suffix for country specific.