https://itsfoss.com/lightweight-linux-beginners/
Puppy Linux latest release is Puppy Linux 6.0.2 tahrpup CE that is only 199 – 201MB in size. Yes! It’s very small. This small Linux distribution can be booted with a small size USB stick.
The Quirky 7.0.3 release is even smaller than tahrpup CE, it is only 176MB.