
I also have a gigabit media converter but I needed it for 100Mbps and you can't easily find one that can do both over fiber. So far, this works well with Cisco and Comnet SFP modules.

π Gigabit Ethernet Media Converter, Single Mode Dual SC Fiber, 1000Base-LX to 10/100/1000Base-Tx, up to 20km, 2-Pack
9 Review

π‘ Izokee ESP-01 Serial WiFi Transceiver Module with USB Converter, Compatible with Arduino
8 Review

TRENDnet TC-TP1 Network Signal Testing Probe with Adjustable Volume, Speaker and Compatibility for TC-NT2
8 Review

π‘ CM19A R.F. PC Transceiver for X10 Devices
8 Review

π Juiced Systems Silver BizHUB USB-C Multiport Gigabit HDMI Hub with 3 USB 3.0 Ports, Gigabit Ethernet, 4K HDMI, SD/Micro SD, and USB-C Power Delivery
11 Review

π uni USB C Hub with Ethernet Adapter, 4K HDMI, Gigabit Ethernet, and 3 USB 3.0 Ports for MacBook Pro, iPad Pro, XPS
11 Review

π CERRXIAN RS232 to Ethernet Serial Device Server - TCP/IP Converter with 1Port DB9 RS232 Serial to Ethernet Connectivity
3 Review

UGREEN USB 3.0 Ethernet Adapter Hub with RJ45: Fast Gigabit Ethernet Converter, 3 Ports USB 3.0 Hub Compatible for MacBook, iMac, Surface Pro, Chromebook, Laptop, PC
11 Review