Unless I am not understanding, Excel should autocomplete names used in your equations via a context list based on your defined names and Excel reserved names.

For instance, if I have a defined name "AverageBin" and start typing in a formula beginning with "=2.5*av" a context list will appear with a list of functions and names that begin with "av" and there is AverageBin right between AVERAGEA() and AVERAGEIF(). You can navigate the list with arrow keys and choose one by pressing tab.

It's really useful if you have defined tables. Say I have a table called Inventory with fields Part, Received, Qty. If I start typing a formula "=inv", the context list pops up and there's my table. I press tab to select it and then type in a left bracket i.e. "=Inventory[". Another context list now pops up with all my fields (Part, Received, Qty).