Pathfinder 1e Pdfs [work] <PC>

: The official license partner. It contains every rule, monster, spell, and item from the 1e books for free, legally.

For specific recommendations on which PDFs are "essential" or "solid," these communities often have pinned threads: pathfinder 1e pdfs

The Pathfinder 1E PDFs include:

Dynamic linking & cross-referencing within the official Paizo Core Rulebook PDF (and compatible rulebook PDFs) : The official license partner