It seems that I can only use a pcie network card to add another LAN port. Is it ture?
Well, it is true to some extent. There is only one CEM slot available in Jetson-Xavier. But, there are two more slots of different form-factors (one M.2 Key-E and the other one being M.2 Key-M) available along with the CEM-x8 slot.
Having said that, M.2 Key-M slot is sandwiched between module and baseboard, so, it can pretty much be used only for connecting M.2 Key-M form-factor NVMe cards.
M.2 Key-E slot is on the backside of the board and there are many WiFi cards available in this form factor. Any WiFi card for which the driver is available in the kernel can be used directly to get one more network interface (i.e. WiFi interface). Well, if your requirement is specifically to have an Ethernet LAN, then, you may need a converter to convert M.2 Key-E slot to a CEM slot and then connect any standard NIC cards (if you are seriously thinking about this option, please make sure that the dimension of the converter is such that it would fit within the space available on Jetson-Xavier board)
Another option would be to connect a PCIe switch to the available CEM slot and extend the availability of the number of PCIe ports (if your budget allows it)
I find a tested card list here Can the cards in the list work without additional drivers? Or I have to find the corrsponding driver and install it
Well, almost for all these cards, drivers are available with the kernel. In any case, to double confirm, just before buying, you can check the specifications sheet and see the controller used in the card and see if the kernel has the driver available.
If you have added an additional LAN ports, can you tell me which card you use and give me the install manual? Both 1Gb/s network card and 10Gb/s network card are ok for me
I would go with something like https://www.amazon.com/Realtek-Chipset-Ethernet-Interface-Software/dp/B007MWYCG2