This new add-on board for the Raspberry Pi gives you an HDMI Input
Raspberry Pi HDMI to CSI-2 adapter board HDMI input to 1080p 25fp - AliExpress
Amazon.com: Geekworm KVM-A3 Kit with Raspberry Pi 4 Case & 20W 5V 4A USB Type-C Power Adapter Compatible with Raspberry Pi 4 Model B Only : Electronics
HDMI input on a Raspberry Pi - YouTube
Raspberry Pi HDMI-compatible to CSI-2 C779 Module, inpute supports up to 1080p25fps - AliExpress
Raspberry Pi 4 Model B - 2GB
I2C Shield for Raspberry Pi 4, Pi 3, & Pi 2 with Outward Facing I2C Port Terminates over HDMI Port - NCD Store
Raspberry Pi 4 Model B - 8 GB RAM : ID 4564 : Adafruit Industries, Unique & fun DIY electronics and kits
Micro-HDMI to HDMI Adapter Cable for Raspberry Pi 4B 1.5M 4K Data Tran – Hiwonder
Raspberry Pi 4B Board for Image Processing Deep Learning Programming
Amazon.com: Geekworm Hdmi-in Module for Raspberry Pi, Hdmi to CSI-2 C779, Hdmi inpute TC358743 Supports up to 1080p25fps Compatible with Raspberry Pi 4B/3B+/3B/Pi Zero/W/2W : Electronics
Raspberry Pi | Raspberry Pi Camera | C790 | C790 Camera | Raspberry Pi CM4 Camera - Aliexpress
Geekworm Raspberry Pi X630 V1.5 Hdmi to CSI-2 Module
Raspberry Pi 4 Micro HDMI Male to HDMI Female Adapter Converter – Geekworm
Raspberry Pi Micro-HDMI to Standard HDMI, 1m Black
Raspberry Pi 4 2gb 4gb 8gb Starter Kit Board Camera Case Fan Power Supply HDMI | eBay
Raspberry Pi 4 2GB Ram 1.5Ghz CPU with 2 HDMI port / Pi 4B with Wifi & Bluetooth | eBay
Meet The Brand New Raspberry Pi 4 8GB - Latest Open Tech From Seeed
How to set up your first Raspberry Pi | ZDNET
Amazon.com: waveshare HDMI to CSI Camera Adapter, Support HDMI Input up to 1080p 30fps Compatible with Raspberry Pi 4B/3B+/3B/Pi Zero/Zero W,Raspberry Pi CSI Cameras : Electronics
HDMI power circuit on the Raspberry Pi 4 - Raspberry Pi Stack Exchange
Amazon.com: USB Splitter CM4 for Raspberry Pikvm HDMI CSI KVM IP pi ATX : Electronics