We need different neckties for different suits and different occasions. The same goes with tie knots. You need at least a handful of different ways to tie a tie, so that you can choose and pick when you need different knots for different situations.
Many people know one knot or two. Not that they don’t want to learn, but just that they don’t have a good guide. So I found this tie tying chart of 18 ways to tie a necktie from Real Men Real Style to be very handy. It pretty much covers tying methods for most popular tie knots.
The tie knots shown are:
Half Windsor Knot
Full Windsor Knot
St Andrew Knot