How can we amplify magnetic fields?
Like LASER is there anything called Magnetic amplifier, the one which magnifies magnetic fields at a point?

Look let me tell you, there is a lot of difference between amplification and magnification.

In the above question I am considering the magnification of magnetic field (or flux lines) to a point. And not amplification of magnetic fields, a LASER uses a lens to form an image at infinite.

And yes, one can concentrate magnetic fields, concentrate here means magnification or bending them.
You can use many small permanent steel magnets or coils and arrange them in such a way that they are magnified to a certain limit.
One similar case is of the  Halbach array.

A Halbach array is a special arrangement of permanent magnets that augments the magnetic field on one side of the array while cancelling the field to near zero on the other side. This is achieved by having a spatially rotating pattern of magnetisation.

I am not sure if we can do that but assuming that it is possible,it should not be called magnetic amplifier.Magnetic amplifier means the usual amplifier used to amplify the electrical signals.Since early in the 20th century the old vacuum tube amplifiers have been replaced by new magnetic amplifiers where magnetic materials are used as core materials.