"Known methods" refers to techniques or approaches that are already understood, documented, and widely used to achieve a certain goal or solve a specific problem.
Sentences with «known methods»
A popular but less known method of bodybuilding is using solely your body weight to build muscle. (en.wikibooks.org)
The first, best known method, is to create effects through pattern and line. (en.wikipedia.org)
I don't know a method for making bread flour, but in a pinch I've used AP and these guys have been tasty still. (takeamegabite.com)