Amazon.com: DTech 4K HDMI Dummy Plug Display Emulator Headless Ghost Adapter Compatible with Windows Mac OSX Linux Support 4kx2k 2160P 1080p for Computer Desktop (fit-Headless, 5 Pack) : Electronics
HDMI Dummy Plug : ID 4247 : $3.50 : Adafruit Industries, Unique & fun DIY electronics and kits
HDMI Dummy Plug 4K Display Emulator Compatible with Windows Mac OSX Linux for Computer Server Remote Access Mining fit-Headless, 3 Pack | Catch.com.au
Full Size HDMI Dummy Plug - For Headless Setup
HDMI Dummy / Carga Fantasma | 4K | Plug and Play | CTE-HDU-01 – Centroniks | Costa Rica