Laptop power adapter connector assortments?

Guys I need help with this - don't know the proper terminology which is hampering search. You've seen these generic rechargers for cellphones at Target and elsewhere that come with an assortment of tips... the part that plugs into the phone - they're non-standard and idiosyncratic per mftr per model, so they sell the charger with a string of five or six different types.
I need the same thing for laptop power supplies... chargers if you will.
I have the P/S, just need to switch the tip - in my case its a gender thing - the barrel diameter and length are right, but the gender is backward.
What do I call this?
Where to find a grab bag of switchers?

 

A multi adapter? =-/