I would love to see people practices around Belbin type roles, talents, types, styles, etc. I think these practices could be helpful for Holacracy implementations, though care is needed to make sure explicit agreement is achieved to use them or else make sure there are no implicit expectations.
Will individuals be expected to participate? Use them? Are they for those with role assigning authority? For self awareness? Relationship building? Finding work more in line with passions and talents? These are the questions that could help shape implementing some people support practices, as I call them.