My mini motherboard has only one PCIE slot which is already occupied. I wanted to upgrade network interface on it to 2.5Gbit/s ethernet.
I used M.2 A+E key format 2.5Gbit ethernet card (Realtek RTL8125B based):
https://pl.aliexpress.com/item/1005004171201464.html
and this is bracket for it. (Sadly, there are no 5Gbit or 10Gbit cards available for the M.2 A+E key. Such cards would be useful, even if they couldn't achieve the full 10Gbit speed)
Printed from PETG with organic supports.
Two variants (the cable was very short, so had to use top variant).
iperf3 results:
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 2.41 GBytes 2.07 Gbits/sec 169 sender
[ 5] 0.00-10.00 sec 2.41 GBytes 2.07 Gbits/sec receiver
The author marked this model as their own original creation.