...F2L, which has tons of guides out there, both written and video, with specialized techniques like multislotting and the like also having their own guides, and all cases have been isolated such that you can go the alg route if you want everything analyzed for you.
Also, most OLL and PLL cases have been optimized to death. The Opticubes site alone has many different versions, including the optimal, 2-gen RU, Rru, RFU versions, etc. Whereas it's hard to find guides for the last step of Petrus and Roux other than the creator's sites themselves. And even then, the options are still unclear (there's CMLL, CLL, COLL for Roux I think, I'm not sure, and then for Petrus, ZBLL seems like the optimal choice, but practically, there's CLL+ELL, or just plain old cross OLL+PLL, or MGLS...)