There are two open source PIM systems written in PHP:

• https://github.com/pimcore/pimcore Pimcore on Wikipedia
• https://github.com/akeneo/pim-community-dev Akeneo on Wikipedia

One written in Go:

• https://github.com/go-pim/go-pim

Proprietary PIM system:

• salsify