I’ve had some success with Atropos from ANTS (An open source multivariate framework for n-tissue segmentation with evaluation on public data - PubMed).
The segmentation tool from FSL is called FAST (FAST - FslWiki).
If you choose FreeSurfer I suggest looking into FastSurfer (GitHub - Deep-MI/FastSurfer: PyTorch implementation of FastSurferCNN). segmentation finishes in half the time.