Hardware

Component	Model
CPU	Intel Core i3-10100 3.6 GHz Quad-Core
CPU Cooler	Noctua NH-L9i
Mainboard	ASRock H510M-ITX/ac Mini ITX LGA1200
Memory	Crucial RAM CT8G4DFRA266 8GB DDR4 2666 MHz CL19
Case	Fractal Design Node 304 Mini ITX Tower
Power Supply	be quiet! Pure Power 11 CM 400W (80+ Gold Certified Semi-modular ATX)
Extension Card	BEYIMEI PCI Express to 2 Port SATA III 6Gbps
Drives	Transcend 120GB SSD SATA III 6Gb/s MTS820S WD Red 6TB 3.5" 5400 RPM (WD60EFRX) WD Red 6TB 3.5" 5400 RPM (WD60EFRX) WD Red 8TB 3.5" 5400 RPM (WD80EFAX) WD Red 8TB 3.5" 5400 RPM (WD80EFAX) Seagate IronWolf 8TB 3.5" 7200 RPM (ST8000VN004) Seagate IronWolf 8TB 3.5" 7200 RPM (ST8000VN004)

At first I bought the Intel Core i3-10100F CPU (F => no integrated GPU), because it did only cost half of what the version with GPU costs and to minimize the power usage of the CPU (why should I need a GPU on a NAS anyway). I wasn't aware that I couldn't even get into the mainboards BIOS/UEFI without GPU, so that did not work.
The mainboard only has 4x SATA III interfaces but the case supports 6x 3.5" drives, this is why I needed the PCI-E extension card (I found no cheap mini ITX mainboard with 6x SATA interfaces)
I opted for the (more expensive) gold certified PSU so that I can utilize as much of the drawn power as possible to save energy and cost
I currently use only one memory module. I plan to upgrade this to two memory modules in the future, so I can utilize dual channel RAM for a bit of performance gain and be more safer in case one module dies.

Component	Model
Hard Drive Enclosure	Xystec 4-Bay Hard Drive Enclosure, USB 3.0 or eSATA
Drives	Seagate Barracuda 5TB 3.5" (ST500DM003) Toshiba 6TB 3.5" (MD04ACA600) Seagate Barracuda 8TB 3.5" (ST800DM004) WD 10TB 3.5" (WD1EMAZ)

I used the USB hard drive enclosure in combination with a Raspberry Pie as my old NAS. Now that I have build my new NAS I did no longer have a usage for it.
All backup drives are from shucked external drives which I used as backup drives in my old setup. I decided it was more practical to combine the external drives into one enclosure instead of having them separate.