Mr. Bill gives ideas...
How bout a candlestick?

Found in most houses to hold candles.
Or how bout a pitchfork?

They can be found out in the country on farms or in a depot store.
Another item suggestion is a hand scythe.

Found once again on farms or in soviet russia :D
Hockey Stick? Golf Club?


Either could be found at a home or store and are fun to use in a zombie killing situation.
Last suggestion for now. A javilin.

It could be a one time throwing obect that pierces and insta kills. I know it's not a melee and we already have a spear but I'm just throwing it out there.