Firmware/BIOS (coreboot, UEFI) (Drivers & Low-level Hardware): open-source projects that exist because someone reverse engineered a closed product, sorted by GitHub stars.
Linux firmware updater with many reverse-engineered device update protocols
Intel/AMD engine firmware (ME, TXE, CSE, PSP) analysis tool
Utility to read and write flash chips on mainboards, programmers and devices
IDA plugin for UEFI firmware analysis and reverse engineering
Editor for UEFI setup IFR forms to expose hidden BIOS settings
Prebuilt coreboot images and flashing docs for ThinkPad laptops
Parses and modifies AMD Platform Security Processor firmware blobs
Extracts UEFI HII IFR setup forms into human-readable text
Go tools and library for parsing and modifying UEFI firmware images
Tool for analysing UEFI firmware modules
Dasharo's coreboot fork with ports for commercial desktops and laptops
GUI to change coreboot CBFS settings via nvramtool
Issue tracker for MrChromebox coreboot-based UEFI firmware for Chromebooks
Patches, mods and docs for the 51nb X210 ThinkPad-derived board
Insyde Software UEFI firmware flashing kernel driver
List of mainboards and their Intel Boot Guard status for coreboot porting
Flash coreboot on MacBooks without an external SPI programmer
Inspect Intel ME/TXE/CSME management firmware images
Reverse engineering of Lenovo IdeaPad Gaming 3 firmware: BIOS extraction and AMD PSP analysis
Parses inteltool PCH GPIO dumps into coreboot pad configs for board ports
Libreboot build system: coreboot board ports, blob extraction and payloads