Re the OP, the cards are probably using one of the Marvel SATA/RAID chipsets. There are many versions of these standard designs around, some are just SATA HBAs, which would be better for ZFS, while others have a RAID BIOS, which isn’t so good for ZFS. I don’t know if they are supported by FreeNAS, but I expect so.
If you look around amazon, ebay, aliexpress, etc you will see a lot of cards that looks like this, and some of them will have useful information like chipset, PCIe confgiuration, etc but don’t trust the sellers to really know what they are selling.
I’ve been looking for one myself since the Marvel chips SATA ports support port multiplier and sometimes I need to connect to enclosures which use port multiplier.
I haven’t found a good card with the combination of bandwidth, chip and ports I like.
Some of the cards are PCIe 1.0 x1, some are PCIe 2.0 x1, some are PCIe 2.0 x2, so between 2.5Gb/s and 10Gb/s bandwidth, which can have a big impact on your performance depending on ports/ssd/hdd combination you are using.
Some of the cards are only PCIe 2.0 x2, but are in a PCIe x4 card, which I prefer to avoid since I might want the x4 slot for something else, and might have another x2 slot elsewhere.
As stated above flashed LSI clone cards are good, I have a couple. If you can find one with IT firmware that you don’t have to flash then that is great, and maybe worth paying a little more. Flashing doesn’t always work out so well, so you can end up with a brick. So far, I have 4 out 5 successes.