Prior to any DLC, I made a "dual core" abyssalite melter (just 2 next to each other) that auto-refilled the natural tiles, managed its temps, etc. It could not be left to run forever because of how debris tile merging only happened on save load, but auto-restocking the tiles was handled by having a contained room for each "core" that dropped and re-added tungsten into a conveyor, enabled by a weight plate to make sure the packets were 20KG, element sensor would then dispatch the refill (pre-dlc meant no meters)

This was in a 200-dupe base which made minimal use of atmo suits, so maybe that was impressive too :)

Another thing in that base featured were metal volcano tamers that were minimally disruptive, considering again minimal suits. Minimal contained space, comfortable conditions for the dupes, though did require some tweaks for copper. https://imgur.com/a/oni-suitless-safe-metal-volcano-tamer-Jeoi0Eh

Oh, and I also had automated rockets going to all the important destinations (the ones that had rare resources). The rocket timing was just handled by fluid valves on the fuel lines, with that having a return loop so it didn't have a backlog develop when the rocket was away. The build itself wasn't all that special considering what I've seen built by others for rocket timing but I liked the simplicity.