This is my script for mirroring FK controls in Maya.
A script can mirror controls like standard Mirror Joints tool with Behavior mirror function.
It can also automatically detect and replace side prefixes/suffixes in control names or remember your custom ones.
Useful for mirroring FK controls when creating your custom rig.
You can buy it here:
Artstation marketplace: https://www.artstation.com/a/23344187
Gumroad: https://riggingpro.gumroad.com/l/MirrorFKctrls