  Many low-threshold experiments observe sharply rising event rates of yet
unknown origins below a few hundred eV, and larger than expected from known
backgrounds. Due to the significant impact of this excess on the dark matter or
neutrino sensitivity of these experiments, a collective effort has been started
to share the knowledge about the individual observations. For this, the EXCESS
Workshop was initiated. In its first iteration in June 2021, ten rare event
search collaborations contributed to this initiative via talks and discussions.
The contributing collaborations were CONNIE, CRESST, DAMIC, EDELWEISS, MINER,
NEWS-G, NUCLEUS, RICOCHET, SENSEI and SuperCDMS. They presented data about
their observed energy spectra and known backgrounds together with details about
the respective measurements. In this paper, we summarize the presented
information and give a comprehensive overview of the similarities and
differences between the distinct measurements. The provided data is furthermore
publicly available on the workshop's data repository together with a plotting
tool for visualization.
