The phrase "neat stack" refers to a group of things that have been arranged neatly and in an organized manner, often placed on top of each other in an orderly fashion. Full definition
Neat stacking of manufactured goods and accepting and stepping of the outbound shipments (bestsampleresume.com)
To keep folded linens organized in neat stacks, flip two shelf brackets on their heads and fasten them to the wall and the shelf with finish washers. (marthastewart.com)
When Warhol displayed facsimiles of Brillo cartons in an art gallery — piled high, in neat stacks, as in the stockroom of a supermarket — he was rephrasing an ancient question: «Given two objects that look exactly alike, how far is it possible for one of them to be a work of art and the other just an ordinary object?» (artmarketmonitor.com)