2
A lot.
Lead guitars usually have six strings - bass guitars have four.
baritone which is designed to tune lower 7 to say 10 string guitars multiscale guitars electric acoustic regular bass 5 or more string basses fretless bass that is off the top of my head
six however you can get 12 string guitars and bass guitars which have only 4 strings the list goes on
Some popular string labels for guitars include D'Addario, Ernie Ball, Elixir, and Martin.
Yes and Yes.
hofner guitars, but i thnk they only make 4 string guitars, not sure, search them though
String instruments
The standard acoustic string gauge used for most guitars is typically light or medium gauge strings.
Some popular string brands for acoustic guitars include D'Addario, Elixir, Martin, Ernie Ball, and Gibson.
No, but there are 20 string guitar harps which very few people can play.
The standard string gauge for acoustic guitars is typically light or medium, with the most common gauges being .012 to .053 inches.