The one that's correct for all 3 my first babies, is this one:
https://www.storknet.com/cubbies/pregnancy/chinesegenderchart.htm
I also like this one, since it works it out for you, accordingly to Lunar months. But, unfortunately it predicted my third child to be a girl, and he's all boy! So it's not correct for all my children.
https://www.chinesefortunecalendar.com/TDB/BabySex.asp
I looked at that first one when we started to TTC this baby I'm carrying. Unfortunately there was a couple of "boy" months and only August and November predicted a girl. I wasn't prepared to wait and just TTC for those 2 months, so I ignored the calender. But, as luck would have it, I only fell pregnant during November! After some 5 months of trying. So who knows? I don't have much faith in these calenders because there's so many different ones out there. But I can't help but hope that one is right for me again.