IK FK Switch
Pairblend two joint hierarchies and connect their output to third joint hierarchy.
For now let's keep it simple. All you have to do is copy the ikfkSwitch.py into your maya script folder (~/Document/maya/2018/scripts for example). Or gitclone this repo there.
In Maya, open the script editor and paste;
import ikfkSwitch # add `from ikfkswitch` before if you downloaded the entier repo. reload(ikfkSwitch) ikfkSwitchUI = ikfkSwitch.ui()
Save this to a shelf; Script Editor -> File -> Save Script to Shelf...
Drag and drop nodes into the boxes, or add selected nodes through the right click menu. Fill out a name and hit apply.