What four science-fiction settings would trade

What widely available technology would Star Wars, Stargate, Star Trek, and Warhammer 40,000 want from one another if faster-than-light systems were excluded?

Replicators are the leading choice for other settings. Star Trek could seek weapons or bacta, while Star Wars could benefit from Stargate's Goa'uld sarcophagus.

Excluding faster-than-light systems makes Star Trek replicators an attractive technology for the other settings. Warhammer 40,000 already has forms of replication, but access is restricted and the available machinery is distinguished from routine Star Trek replication. Its civilizations have ample power generation to support wider use of that technology. Star Trek could seek offensive systems or Star Wars healing technology such as bacta. The Goa'uld sarcophagus is then proposed as something Star Wars would value, despite its mental side effects. Star Wars power-generation technology also interests the Warhammer comparison, which distinguishes warp reactors from the fusion, fission and combustion systems still used across the Imperium.