I'm not too well versed in the 55 set, but there are the same rarities as they are throughout all sets. I collect signed Dodgers so I can give insight to those. I am solely working on signed 52s topps at this time.
Of course Agganis passing in 55 would be the earliest death, but he was very popular, so odds are there are examples, but they will be pricey. I could see a Clemente in an open market heading north of 5K.
Hoak was a notorious non signer.
Spooner blew a world series game, and was tormented by baseball after that and just refused to signed.
Hamric one of those obscure players you hardly ever see signed
Curt Roberts and Bob Trice are both extremely tough and are on many want lists.
Wehmeier and Kinder, are difficult in all years
Hodges doesnt come up very often, for a star you'd think he would. Maybe being in the high series hurt that, who knows
A few red sox and a couple tougher cards
Bilko d 78
Hack d 79
