What kind of secondary payloads do commercial launches frequently offer for a fee, unlike many government missions?

Answer

Memorial or promotional slots

Commercial launches often provide services for private payloads, including the inclusion of memorial or promotional items for a fee, distinguishing them from government missions which prioritize scientific return.

What kind of secondary payloads do commercial launches frequently offer for a fee, unlike many government missions?
Spaceexplorationrocketssatellitesspacecraftlaunch