Renamer is an add-on that provides advanced batch renaming capabilities within Blender. It allows users to rename objects, collections, materials, textures, node groups, armatures, and actions simultaneously. The tool includes features for finding and replacing text using wildcards or regular expressions, adding prefixes and suffixes, and converting text cases such as snake_case or camelCase. Additionally, it supports hierarchy-based naming, left/right symmetry pattern recognition for rigging, and synchronization of object names across meshes and data blocks.