Here's a piece of the King recently offered on eBay:
Amusingly, and I realize it's hand cut, centering was an issue even on the samples! There's no way that left border measures out:
Here is what the complete 3 card sample strip looks like:
I realize 50,000,000 Elvis fans can't be wrong, but neither was $50,000:
After Elvis, the next fad was TV Westerns and Monsters. I can't find my scan of a 1959 You'll Die Laughing sample so it's the former and these two fit together like a puzzle. The third card must have been excised more cleanly.
The back of this one has a bit of design; Topps was starting to move past basic text on these once the Bowman purchase was out of the way, or so it seems
I can't find an intact 3 card TV Westerns sample, so you have to imagine the last card! I always thought it odd the set had 71 cards but the above titles match the issued set. Either a series they planned to include didn't work out as the count should probably be either 77 or 88 cards or they had trouble obtaining individual rights to a certain actor or two that screwed up the normal "divisible by 11" set count of the era. Maverick is a notable gap in their offering so maybe it was an inability to get a release from James Garner or even John Kelly that caused the truncation.
I'll close with a really sweet batch of 1963 Football. These are three but perhaps that count is low? Take a look:
The backs look like so:
Either that's a "four" or an alternate back exists. Sometimes wholesaler's (jobbers) samples left space for an address. Love the use of the green on the reverse but it should extend to the right a bit more on the third card, along with the text.