Extra Storage Tanks: Steel Storage Tank
All credit goes to the authors of the original mod, Extra Storage Tank, which are Aurora & Moonlight publishing under the username of Anicha. Since they seem to not have been active for a long time, I have taken it upon myself to port their mod to Factorio 2.0, while improving some aspects of it. And since they applied a generous license to it (MIT), I figure its okay for me to do this. I also intend to maintain the mod for a good while.
Features: The mod adds the Steel Storage Tank. It has a 7x3 footprint with two eccentric pipe connections, and may be rotated before placement. Capacity has been raised from 75k to 125k units (estimated from its visuals), the amount now being configurable as well! Tech research cost was reduced, because it felt too high for just a bigger tank (you still need to research Concrete). Recipe ingredient cost was decreased overall as well, for the sake of balance, to more accurately reflect the physical dimensions, and to make the steel tank more steely.
Graphics: New circuit connectors were created and properly fitted to the tank, and custom remnants were created through some patchwork and colorization of existing base game assets.
Note on space efficiency: Compared to the Storage Tank, a single Steel Storage Tank holds the same volume within 45% of the space, while larger arrangements will have a rectangular footprint of 55-72% (depending on layout), due to the odd pipe connections. They are a noticeable improvement in any case.
Check out the related mod, Extra Storage Tanks: Tiny Storage Tanks, as well!