preprepare
The pre_prepare module aims to prepare all your statements as soon as
possible and in a way that allows client queries not to bother at all and
just call EXECUTE. It's a C-coded PostgreSQL extension in order to be able
to preload it at backend start, but local_preload_libraries currently can
not initialize SPI, so it could be a simple plpgsql script.
See preprepare at GitHub.