Poly Haven is described as 'The Public 3D Asset Library' and is an website in the photos & graphics category. There are four alternatives to Poly Haven, not only websites but also apps for. The best Poly Haven alternative is OpenGameArt.org, which is free. Other great sites and apps similar to Poly Haven are ambientCG, Poliigon and Quixel Megascans.
OpenGameArt.Org is an online asset repository of freely licensed graphics, models, sounds, & music for use in free & commercial games & other media.
ambientCG (previously CC0Textures.com) is a free material resource for PBRs, HDRIs, models and textures licensed under Creative Commons Public Domain (CC0).
Quixe Megascans is a massive scan library. Megascans provide assets for games, vfx and much more. It's contents are 3D assets, vegetation, decals, tileable surfaces.
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The page should have PBR materials with normal, AO, roughness and color maps at the very least.