Religion:

Canons of the Seven Ecumenical Councils

Reverent Catholic Mass Finder

St. Ambrose's Exposition of the Faith

St. Seraphim of Sarov: On the Acquisition of the Holy Spirit

Philosophy:

William James - Essays in Pragmatism

Russel Kirk's Essays

From the Phenomenology to the Mechanisms of Consciousness: Integrated Information Theory 3.0

Linguistics:

Learn Latin with the Dowling Method

Collar and Daniell's First Year Latin

The Sapir-Whorf Hypothesis and Probabilistic Inference

Music:

John Fahey Guitar Tabs

Science:

Sci-Hub: Get free access to literature

International Chronostratigraphy Chart

Semiconductor Physics & Devices (4th Ed.)

Solutrean Hypothesis: genetics, the mammoth in the room