Resource Collection Drone

I think it would be really useful to have a small drone that players can send to collect resources from places they’ve already explored. It could help gather materials from deep caves or dangerous areas without replacing exploration.
To keep it balanced, the drone could have limited storage, a battery that needs to be recharged, and a chance of getting damaged or lost in high-risk biomes. That way, it wouldn’t replace the player, but it would make collecting resources in the late game much less repetitive.
I think this would be a great quality-of-life feature while still keeping exploration as the main focus of the game.

Like a mini unmanned submersible that goes and collects materials that weren’t gathered or when your inventory is full

I really like this idea assuming its supplemental. Honestly all you really have to do is make it slow to keep the player relevant. I’d make it expensive and scaleable. So getting one is a major investment and it doesn’t spiral into infinite resources too fast.

What I would change about what you said is I wouldn’t let it go in caves, or at least wouldn’t let it go deep. This is in essence a exploration game and cave diving is a massive aspect of that and is one of the most dynamic aspects. Plus then you could’t rely on it for absolutely everything. Keeping it more surface level means for the more rare and valuable materials you need to fetch yourself so it doesn’t nullify late game exploration.