Oddly enough there is one of these currently on ebay - Al Kaline card that was quite obviously part of a larger card panel (appears to be torn apart from at least one other card)
https://www.ebay.com/itm/1958-TOPPS-...UAAOSwr-hfaG6h
Also note that 58 Topps had 2 (regular issue) "Insert Cards" advertising a "Felt Emblem" Redemption and a Felt "Initial" Redemption.
https://www.ebay.com/itm/1958-Topps-...cAAOSw9Epfg6ep
https://www.ebay.com/itm/1958-Topps-...MAAOSwX9ldeCoE