First under appreciated player that pops into your head

[BillyCoxDodgers3B]

I'm definitely just judging by the way their contemporaries whom I knew spoke (or didn't speak) of them. When I visited all these players many years ago, I would tend to listen more than talk, letting them discuss whatever and whoever they wished for as long as they wished. I never wanted to interrupt the conversational flow. Heilmann was a man the older players would bring up on their own, and his talent was universally recollected with a great deal of respect. Vaughan was from the next generation down, and I got to know even more players from this era, including a significant number of his teammates. His name was barely mentioned, so perhaps he was overlooked by his own colleagues as well.

I certainly agree with your other point that there are a great deal of HOFers mentioned in this thread. Musial, Frank Robinson and Spahn have been brought up a lot. These guys were considered among the elite by those who saw them play. I'm not sure why anyone considers them overlooked based on their caliber of play. I'd agree on your assessment that this pertains more to card values.