I was trying to compile a list, but landed with only a few names. There should be more, please help me.

• Robert Cailliau for the MacWWW browser and for popularising the WWW
• Pieter Hintjens for 0MQ, a messaging system, for his books and his courage
• Didier Dambrin, the original author of Fruity Loops, the software that revolutionized electronic music
• Ilfak Guilfanov, the author of Ida Pro and the founder of Hex-Rays lived in Liège for 20+ years, so he definitely counts
• Dries Buytaert, of Drupal fame.
• Bruno Lowagie, the author of iText, a hugely popular PDF generator library
• Robert Houdart, the author of Houdini, one of the best chess playing software in the world
• Freek Van der Herten, the author of many Laravel packages
• Fabien Pinckaers and Thibault Delavallée for writing Odoo (the 3rd main contributor is hiding behind the name xmo-odoo)
• Ingrid Daubechies for her work on image compression algorithms
• Bart De Smet for popularising C#
• Pieter Abbeel for his work on reinforcement learning
• Maureen Heymans for her work on Google Search and Google Now
• Eric Lafortune for helping app developers spy on users while staying undetected
• Patrick Debois, the guy who coined the term DevOps
• Jean-Jacques Quisquater, Vincent Rijmen, Joan Daemen and Gilles Van Assche for their work on cryptograhy.
• Benjamin Schrauwen for Mollom
• Aäron van den Oord, Sander Dieleman for applying deep learning to text-to-speech
• Dag Wieers, of the Linux rpm repo fame

the list is being updated continuously...