HTC has added two additional flavors of EVO 3D to its bootloader unlocking site, following in the footsteps of the Sprint version, which become unlockable last month. If you own an unbranded European EVO 3D, or a Rogers-branded device in Canada, then you can begin your quest by using the web tool over on the HTCDev site.
Unlocking your bootloader will allow you to monkey around with custom firmware and the like, though you'll void your warranty by doing so, even if you use the official HTC unlocking tools. Still interested? Hit the link below to begin.