The @Levenger window pane 3x5 cards are perfect for presentations because landscape leaves a blank area for your thumb.

These are “official” Hallmark 3 x 5’s. The story goes that the founder of Hallmark, J.C. Hall, asked the pressman to trim down the waste bits of paper into 3 x 5’s for him to write notes. He was seldom ever seen without a handful in his pocket and soon others were asking if they might have a stack.