Retargify is a Blender plugin from Haggets that overhauls Rigify, adding quality-of-life improvements to make rig setup faster and the animation process easier. It remains Rigify at its core, so existing Rigify tutorials and knowledge still apply without major changes to the overall process.
The plugin works non-destructively through armature duplicates and constraints that are created automatically, giving you full control over the armature while keeping the original data intact. You can add, move, and remove bones, and armatures can be updated without losing animation data. Baking transfers animations from the animation armature to the base armature in a single click with 1:1 accuracy, and backwards baking lets you bake motion-captured data onto the Rigify armature to tweak it with Rigify controls.
Quick tools include bone collection presets you can save, reuse, and share, automatic sorting of bones into collections by Rigify bone type, and automatic bone coloring for readability. Note that Retargify does not currently work past Blender 4.4, with updates said to be coming.