California Citizens Redistricting Commission Ballotpedia

The “Iowa Model” for Redistricting4/6/2018
Nonpartisan Staff Draw Maps in Iowa–Legislature Votes on Them

Initiative and Referendum Institute–26 states

States with some form of initiative and referendum:

Michigan Independent Citizens Redistricting Commission in State Constitution
Here is the actual language of the Constitutional Amendment Michigan voters passed with 61% yes votes in 2018 as Proposal 2.