Since 3D Blu-rays are no longer mass-produced for the US market, you have to get creative to find them:
The 3D Blu-ray format gained significant traction following the release of James Cameron’s Avatar in 2009. As the first "Modern 3D" blockbuster, it spurred television manufacturers to adopt 3D capabilities as a standard feature. For nearly a decade, major studio releases routinely shipped with a 3D disc included in "combo packs." all 3d blu ray movies list free
Here's a list of popular 3D Blu-ray movies across various genres: Since 3D Blu-rays are no longer mass-produced for