Recycle it before you bankrupt yourself on electricity

It's also likely to be an energy vampire as well. The DL380G7 was a good server in it's hayday. From a reliability standpoint it still is. But the performance per amount of energy consumed is just not economical. That much said, you could save power draw by replacing the spinning disks with SSDs and make it better but the G7's processor will be anemic by today's measures.

The problem with these older units is that we have come so far in terms of performance per watt that the cost of electricity quickly makes them irrelevant.

I used to run a cluster of Dell 710s that I was able to replace with a few M720q very cheaply off eBay and run the same workloads at less than 1/3 the power usage (even better at idle, since that really where these old units don’t do well).

I have seen a few converted into DAS or drawers for a rack, but you’d have to already have a rack for that to be useful or worthwhile.

Do you have access to the iLO? If so, you shouldn't need anything else

The internal usb and SD card slot are just there in case you want to boot from usb or SD.

You can install your OS to them and then all of your HDDs can be used for storage instead of losing capacity to an OS partition.

Back in the day, we would look for the newest SmartStart CD to install from, but it's no longer possible to get from official channels. Also they're only useful for installing the supported operating systems.

The G7 knows the thermal profile of most HP hardware of it's generation and runs the fans at the appropriate speed for proper cooling for known hardware, but sticking anything 3rd party (or just newer) in there will ramp it up to max cooling mode for thermal protection. It's a pain.