Ultra-high-energy (UHE, $E \gtrsim 10^{17}\,\text{eV}$) photons are expected to originate from the interaction of UHE cosmic rays with background radiation fields, as well as from more exotic processes like the decay of hypothetical super-heavy dark matter particles. UHE photons produced at cosmic-ray sources are key ingredients for enhancing our multimessenger understanding of the cosmic-ray acceleration and transient phenomena. Pierre Auger Observatory, designed to investigate UHE cosmic rays, offers unparalleled sensitivity to UHE photons. In this contribution, we present recent results of photon searches above $10^{16.7}\,$eV obtained with data collected prior to the upgrade of the Observatory. Additionally, we discuss directional and follow-up searches conducted in coincidence with gravitational wave events detected by LIGO/Virgo, highlighting the role of the Observatory in advancing multi-messenger astronomy at the highest energies.