Great Ball Catalog

GBC Module Catalog

About the Great Ball Catalog

Great Ball Contraptions (GBC) modules are custom-built LEGO machines that transport small LEGO balls through creative mechanisms.

This catalog is the world’s most comprehensive resource for GBC modules, featuring hundreds of modules from dozens of builders, a lot of them with build instructions. Whether you’re a seasoned builder or just discovering the hobby, you’ll find hundreds of unique designs to explore and build.

Start browsing to discover the amazing variety and ingenuity of the global GBC community.

How Videos are Found

Our video listings come from regular searches on YouTube for the terms "LEGO GBC" and "Great Ball Contraption". We periodically query for new uploads, review results for relevance, and surface videos that clearly feature GBC modules or runs.

Privacy Policy

Please see the Privacy Policy page, which includes a form for you to update your cookie preferences.

Disclaimer

Great Ball Catalog is an independent, fan‑run site and is not associated with, sponsored, authorized, or endorsed by The LEGO Group. LEGO® and the LEGO logo, the Minifigure, and the brick and knob configurations are trademarks of the LEGO Group of companies. ©2025 The LEGO Group.

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Great Ball Catalog
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  • Homepage
  • The GBC Standard
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Great Ball Catalog is an independent, fan‑run site and is not associated with, sponsored, authorized, or endorsed by The LEGO Group. LEGO® and the LEGO logo, the Minifigure, and the brick and knob configurations are trademarks of the LEGO Group of companies. ©2025 The LEGO Group.

Get in touch

If you build GBC modules, join our Discord server and get in touch with other GBC builders just like you!

  • Great Ball Catalog Discord

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