In GNU Emacs 25.0.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.24.23)
  of 2015-10-29
Repository revision: 07830c3d5c801d7d55622215b46ba692c6afa1d2


I found very useful to define one function returning:
(nreverse (last (nreverse list) N))
(for a given list and integer N)

Maybe its already defined somewhere, but i cannot find it.

Examples of the new function:
(let ((ltest '( 1 2 3 4 5 6)))
   (nfront ltest 3))
(1 2 3)

(let ((ltest '( 1 2 3 4 5 6)))
   (nfront ltest 1))
(1)

(let ((ltest '( 1 2 3 4 5 6)))
   (nfront ltest 20))
(1 2 3 4 5 6)

(let ((ltest '( 1 2 3 4 5 6)))
   (nfront ltest))
(1 2 3 4 5 6)