thinking of a new belt method. Not sure if this has been proposed before, but here it is.
1: permute 3 cross edges and make a belt around the cube.
2: insert the last cross edge quickly with M moves.
3: insert the f2l corners. You could do a last slot method on one of the last corners but it depends since some cases might not have algs that make the pair, then insert it. For example when you have a case where you have a corner which white is on top, and the f2l edge is solved (this is a white cross solve), you can do it by RURURURUR insert. But to do a last slot method to orient EO, URURURUR would be much more optimal.
4: solve last layer by any method you want.
Pros: you dont have to make a full cross, only 3 cross edges, which means that the first step will be more easy, and more cross tricks might open up, as well as your cross time decreasing.
For belt, there is alot of freedom, which means while inserting edge pieces, it could open up to more belt tricks to make the belt step more efficient and faster.
the corner permutation is pretty simple and fast.
Edit: Another pro is that you can use CLS everytime.
Cons: doing Belt and Corner permutation is slower than doing F2L.
Look-ahead is very hard.
Pieces can be hidden almost anywhere during belt, making it very hard to find pieces without multiple rotations.
This method just isnt as fast as other methods, like ZZ, Petrus, Roux, or CFOP. But it could still be used as a speedsolving method. It is also pretty simple, meaning that it could be used as a method for beginners.
idk what to call this method.