While individual maps are often hosted on sites like The Hive Workshop , large community-curated packs are frequently shared via Google Drive links in gaming forums.
Once you have located a trusted Google Drive link from a community source like Reddit's Warcraft 3 community : How to add in custom map to my game after download download warcraft 3 full map google drive
Some "archaeological" packs focus on pre-2006 maps or version 1.27b classics for nostalgia-driven play. Step-by-Step: How to Download and Install While individual maps are often hosted on sites