Thought I'd list this instead of throwing it out, just in case anyone is tearing their hair out trying to find one.
I/O Shield / Backplate for Intel DH55TC Motherboard May Fit Other Intel Models
CPU Cooler Backplate for Intel AMD AM2 AM3 AM2+ AM3+ Motherboard, Strong Heat Dissipation Metal Backplane
BODYA 2Pcs I/O Shield Replacement Without Any Opening Blank Backplate for All Motherboard DIY
AM4 COOLER MOUNT BRACKET + BACKPLATE FOR X570 / B550 / B450 AMD BOARDS - UK STCK
5PCS I/O shield no any opening blank backplate for All motherboard DIY Nice
AM4 HEATSINK RETENTION BRACKET + BACKPLATE FOR B450M / B550M MOTHERBOARDS - UK