Hardware Crackmes: 100 GameBoy Advance Games
A Game Boy Advance cartridge is a frozen binary. There are no patches, no server-side validation and no telemetry. Whatever cheat codes the developer intentionally (or unintentionally) wrote in 2003 is still the exact code running today. That makes an in-game cheat code about as close to a real-world crackme as you can get: there is a validator, there is an input surface on dedicated homogenous hardware, and somewhere in the ROM is the set of inputs it accepts.