I recently rectified a major gap in my collection with the acquisition of one of the best Jackie Robinson cards there is: his 1955 Topps offering. I have his '56 Topps but '55 was a must for so many reasons, starting with the World Series title tie-in.
Add in how gorgeous the card is and I couldn't jump fast enough when one ended for a more than reasonable price and looking ungraded by a full grade. It's the "full diamond" version and there's literally nothing about this card that isn't sublime.