CR4
From Speedsolving.com Wiki

CR4 or CRoux4 (CriticalRoux4, longer name) is a Rouxbased method proposed by CriticalCubing in 2017 for solving the 4x4x4 using Roux method principles. He posted this method initially in the "Roux Method Speedsolvers" facebook group as an alternative to Meyer method, which is what most Roux users use for solving the 4x4 cube.
CR4 can also be applied to bigger cubes, but its reliance on M slice will be a con as M slices becomes difficult to use on bigger cubes.
Contents
Overview
The CR4 Method consists of 7 steps;
 Two opposite centres. One of them will become your First Block Center.
 Blockbuild a 1x3x4 block. You can make it on either of the two centers.
 Complete two adjacent centers + one random edge. Keep the centers on D and B slice, keep the edge in DB position.
 Pair up 3 edges and keep them on R slice.
 Complete the Last two Centers (use slice moves)
 Finish Edge Pairing
 Do 3x3 stage with Roux (first block is already solved)
(Look at the example solves in the CR4 doc for more information)
Pros
 Small number of rotations required. 3x3 stage is completely rotationless.
 M Slice method of pairing is ergonomic.
Cons
 Reliance on M slice. Using M slices becomes difficult on big cubes.