Curt Simmons signed his 1952 and 1963 Topps.
Lew Krausse signed his 1963, 1968 and 1969 Topps.
Mel Nelson signed his 1964 and 1966 Topps. He also answered my question about his time in Minnesota, of which he recalled a "short summer".
George Thomas signed his 1963 and 1967 Topps.
Daryl Spencer signed his 1956 Topps and also enclosed a 2012 Baseball Magazine card.
Finally, Don Kaiser signed his 1956 and 1957 Topps.