What are these long gold plated SMD components on the NVidia Tesla A100?
It seems like this is a Power-On-Package from Vicor.
They call these modular current multiplieres (MCM) and they are basically step down converters. They aim to drive these with their modular current drivers (MCD) with a voltage of up to 48V from the mainboard and step the voltage down only a few cm from the current hungry IC (that might draw up to 640A peak\$^1\$), to reduce power losses in PCB traces and socket pins.
On this page they say that NVidia uses these modules for the AI accelerators.
\$^1:\$ Disclaimer: Marketing data


Image source: Vicor Website