General Knoppix support for those who've read the FAQ at the Wiki
Cisco SG110 24 Port Gigabit Ethernet Switch w/ 2 x SFP SG110-24
$117.00
Cisco Nexus N55-D160L3-V2 2 Ports Daughter Card Expansion Module 1 Year Warranty
$395.00
Cisco SFP-25G-SR-S 25GBPS Multi-Mode SFP+ Transceiver Module 1 Year Warranty
$333.00
Cisco WS-X4712-SFP+E 12-Port 10GbE Line Card SFP+ Module Catalyst 4500E Series
$94.99
Genuine Cisco SFP-10G-SR V03 10GBASE-SR SFP+ Transceiver Module 10-2415-03
$8.00
For Cisco SFP-10G-T, Ubiquiti UF-RJ45-10G Module 10G SFP+ to RJ45 10GBase-T
$48.59
NEW Sealed Cisco SFP-10G-SR-S 10G SR SFP+ Module 850nmMM *US Shipping*
$15.00
GENUINE Cisco SFP-GE-T EXT 30-1421-01 USA 1000BASE-T RJ45 SFP Transceiver
$9.99
10 PCS Cisco GLC-LH-SMD 10-2625-01 1310nm SFP Transceiver Module
$85.00
2.5GBase-T 2.5G SFP-T to RJ45 Copper Transceiver Module For Cisco,Ubiquiti UniFi
$24.59