I recently learned of Telescript[1], a programming language, design to allow clients to execute arbitrary code on servers.
SQL databases also have a similar architecture, with the code being executed being much more restrained but still powerful.
What other systems were designed with remote code execution as a feature?
[1] https://en.wikipedia.org/wiki/Telescript_(programming_language) and I got it from this video https://www.youtube.com/watch?v=RLF7yfXFmUk