ZZ F2L

Blockbuilding the first two layers with R, U and L only.
With EO done, the left and right 1x2x3 blocks are built around the line using only R, U and L turns. Most solvers build the left block first (with L and U), then the right block (with R and U). The pieces are all oriented, so pairs form in fewer cases than in CFOP's F2L and no rotations are needed.
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    Build a 1x1x3 or a 2x2x1 square first, then extend it to the full 1x2x3 block.
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    Keep to R, U and L: an M turn would move the centres the line and the blocks are built around.
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    For the last pair of each block, the ordinary F2L insertions that avoid F and B work unchanged.