  When observing astronomical objects, we must deal with extinction (i.e. the
absorption and scattering of the emitted radiation by dust and gas between the
source and the observer). Interstellar extinction depends on the location of
the object and the wavelength. The different extinction laws describing these
effects are difficult to estimate for a small sample of stars. Many
sophisticated and automatic methods have recently been developed for estimating
astrophysical parameters (age and metallicity, for example) depending on the
reddening, which is usually treated as a free parameter within the
corresponding estimations. However, many reddening values for stars have been
published over the last few decades, most of which include observations in the
ultraviolet, which are essential for a good estimation but are essentially no
longer considered. We searched the literature through the end of 2022 for
published independent reddening values of stellar objects based on various
methods that exclude estimates from reddening maps. In addition, we present new
reddening estimates based on the classical photometric indices in the Geneva,
Johnson, and Stromgren-Crawford systems. These are based on well-established
and reliable calibrations. After a careful identification procedure and quality
assessment of the data, we calculated the mean reddening values of 157 631
individual available measurements for 97 826 objects. We find several
statistically significant offsets and trends within the different references
and discuss possible explanations for them.
