I found a intellisense setting in Visual Studio for Mac that makes me write code way faster. I turned on "Show import items", after that I will get code completion even for classes that are in namespaces that I don't have added a using for. I think it makes me write code faster and it help me to find classes that I'm not completely sure what the name is.
To turn it on open "Preferences" and go to "Intellisense" under the "Text Editor" header. And then check "Show import items"