  We employed a machine-learning assisted approach to search for
superconducting hydrides under ambient pressure within an extensive dataset
comprising over 150 000 compounds. Our investigation yielded around 50 systems
with transition temperatures surpassing 20 K, and some even reaching above 70
K. These compounds have very different crystal structures, with different
dimensionality, chemical composition, stoichiometry, and arrangement of the
hydrogens. Interestingly, most of these systems displayed slight thermodynamic
instability, implying that their synthesis would require conditions beyond
ambient equilibrium. Moreover, we found a consistent chemical composition in
the majority of these systems, which combines alkali or alkali-earth elements
with noble metals. This observation suggests a promising avenue for future
experimental investigations into high-temperature superconductivity within
hydrides at ambient pressure.
