The dataset consists of three parts:
The first part is the recalibrated UBVRI standard star catalog from Clem & Landolt (2013, 2016), containing about 47,000 standard stars with brightness roughly in the range of 12 < V < 22. Under the condition of G < 16, the recalibrated results show consistency with those derived from the Gaia DR3 BP/RP synthetic photometry method (XPSP) at the levels of 48 mmag in the U band, 11 mmag in the B band, and 5-6 mmag in the VRI bands. This catalog also includes our quality assessment results for several hundred photoelectric standard stars from Landolt (1992).
The second part is a catalog of about 5.4 million UBVRI standard stars generated using the stellar color regression (SCR) method, based on Gaia DR3 photometry and LAMOST DR12 stellar atmospheric parameters. Compared with the XPSP results, the consistency reaches 28.1, 6.7, 3.5, 2.7, and 2.6 mmag in the UBVRI bands, respectively, under typical conditions of V ~ 14 and SNRG > 15. Further tests show that this catalog generally achieves higher precision in the U band than the XPSP-based results.
The third part provides extinction coefficients for the UBVRI bands as functions of temperature and extinction, consistent with those listed in Table 2 of the paper. 
For more detailed information, please refer to our paper (Huang et al. 2025b).