UPSC Website – Official source for all previous year papers.

InsightsIAS – PDFs of all sets (GS & CSAT) available.

ClearIAS – Free download of papers with answer keys.

Testbook – Set-wise question papers and solutions.

Adda247 – Download GS and CSAT PDFs.

Drishti IAS – Prelims papers in Hindi & English.

PWOnlyIAS – Both papers with answer keys provided.

Shiksha – Live analysis and paper updates.

Vision IAS – Usually uploads memory-based papers.

YouTube Channels – Quick access via exam analysis videos.