A lot of useful semiclassical physics is done based on Bohr-Sommerfeld quantization. In particular, modern versions of it are indispensable in the spectroscopy of large molecules, where the more accurate ab initio methods become numerically too demanding.
- Norcliffe, A., & Percival, I. C., Correspondence identities II. The Bohr-Sommerfeld identity for the hydrogen atom. Journal of Physics B: Atomic and Molecular Physics, 1 (1968), 784.
- Colwell, S. M., & Percival, I. C., The semiclassical determination of potential surfaces from observed spectra. I. Chemical Physics, 75 (1983), 215-223.
It is also used for meson spectra in constituent quark models:
https://arxiv.org/pdf/hep-ph/0412170
and for the analysis of black holes:
https://arxiv.org/pdf/1204.1699
to mention just a few more recent uses.