With Transformers being such a popular brand with a well-spread-out fan base, numerous unofficial conventions have sprung up over the years, often featuring many guests who worked on official Transformers projects.
- BotCon 2004
- June 19-20 2004 - Pasadena, California. Yes, there was an unofficial BotCon.
- Iacon One
- July 7-8 2006 - Grand Wayne Convention Center, Fort Wayne, Indiana.
- TransformersCon 2002: November 10th - Hamilton, Ontario
- TransformersCon 2003: June 22nd - Burlington, Ontario
- TransformersCon 2004: March 12th - 13th - Toronto, Ontario
- TransformersCon 2005: March 25th - 26th - Toronto, Ontario
- TransformersCon 2006: April 28th - 29th - Toronto, Ontario
- TransformersCon 2007: April 27th - 28th - Toronto, Ontario
- TFcon 2008: June 20th - 21st - Toronto, Ontario
- Transcon II: July 1997 - Chicago, IL.
- Transcon III: September 1998 - Toledo, OH.
- (Held simultaneously with "Microcon", a Microman convention, and "Megocon".)