AV Latency.com Toolkit
Tool for accurately measuring HDMI and S/PDIF audio latency
Toolkit webpage
Research wiki
In-depth website on latency and AV sync
Relative Controller Input Lag
Analog circuit that closes up to four switches (presses up to four buttons) at the same time
Super Smash Bros. Ultimate: GameCube vs. Pro Controller input lag
View video
Nintendo Switch Pro Controller: Wired vs. Wireless input lag
View video
Super Smash Bros. for Wii U: GameCube vs. Pro Controller input lag
View video