This is a weirdly worded question... Are bạn asking who is the best pirate in OP? And what do bạn mean bởi 'best'...? The best fighter? The best Captain? hoặc best all round pirate? I'll go with the latter, and say Whitebeard, because all-round he was probably the best pirate - at least, until he died.
although the manga/anime say whitebeard and gol d roger stalemate a lot, gol d roger still has a d in his name and it could be the reason why he is stronger plus there is the fact that no one really knows the strength of monkey d dragon who i feel is the strongest especially if he can control the weather that would be cool