In chronological order:
The Book and the Sword: Huoqingtong and Li Yuanzhi HUOQINGTONG AND LI YUANZHI. Like come ON, the early chapters of the book even have a disguised-as-a-man Li Yuanzhi flirting shamelessly with Huoqingtong, in a rush of power that comes with temporarily being perceived as a man. Also gets them away from their deeply mediocre love interest (Huoqingtong) and husband (Li Yuanzhi).
The Sword Stained with Royal Blood: Wen Qingqing and He Tieshou WEN QINGQING AND HE TIESHOU. Again, come ON, He Tieshou is canonically in love with Wen Qingqing for the chapters where she thinks Wen Qingqing is a man. No shade on our male lead Yuan Chengzhi, but he's frankly BORING and He Tieshou is the queen of sexy banter.
The Legend of the Condor Heroes: Very slim pickings here, in part because I do think Huang Rong and Guo Jing work for each other and in part because the female characters spend very little time together. You could maybe do Huang Rong and Mu Nianci, but that feels too much like pairing the two main female characters up just because they happen to be the main female characters.
Fox Volant of the Snowy Mountain: There's literally only one alive woman with any substantial role in this, so yeah.
(Edited to add: just after posting, I remembered that there IS another young woman, the sweet-seeming-but-secretly-scheming Tian Qingwen, in this story, but the arc Jin Yong gave her was so horrific that I've blotted it from my memory. On that basis, I suppose you could ship her with actually-sweet female lead Miao Ruolan in an opposites-attract/redemptive relationship sort of way, but that would require a ton of extra-textual imaginative work)
The Return of the Condor Heroes: Controversially, I've never felt that Xiaolongnu and Yang Guo's supposed epic romance was particularly well-developed. Jin Yong just spends too little time on that emotional arc. It's just bam! they're master-disciple and bam! they're in love. Anyway
this fic has convinced me that Xiaolongnu would be better off with her shijie and (one-sided) martial rival Li Mochou. Also prevents Li Mochou's entire storyline from being 'she became a badass villain because she was Scorned by a Man'.
The Young Flying Fox: A tough one. Cheng Lingsu has occasional antagonistic chemistry with her romantic rival Yuan Zhiyi, but does Yuan Zhiyi deserve Cheng Lingsu? No she does not, and her motivations and the premise of her character make completely no sense. I think I fundamentally ship Cheng Lingsu with being alive.
White Horse Neighs in the Western Wind: Look, it's got to be Li Wenxiu and A-Man. There's even a bit where Li Wenxiu, disguised as a man, tries to get A-Man away from a terrible captor by pretending she wants A-Man as a slave (though the racial implications of that... yeah).
Blade-Dance of the Two Lovers: I give up, I still can't remember what happens in this.
The Heaven Sword and the Dragon Sabre: Ehhhhhh I guess Zhao Min and Zhou Zhiruo, romantic rivals, have reasonable enough antagonistic chemistry that you could build a ship on that? I know there's been fic written about that. I don't really care all that much about them, male lead Zhang Wuji, or this novel though.
A Deadly Secret: None of the women spend enough time with each other to be remotely shippable, and tbh Shui Sheng and Di Yun work pretty well together as two utterly broken people finding a tiny measure of healing with each other.
Demi-Gods and Semi-Devils: For Reasons, it is IMPOSSIBLE to ship most of the younger female characters together in good conscience, no matter how much aloof-jiejie-x-cute-cinnamon-roll-meimei chemistry you think Mu Wanqing and Zhong Ling have. Still I think A-Zhu and A-Bi (to whom the Reasons do not apply) would be cute: they're basically introduced as a pair, and they live and work together and know each other well. Also gets A-Bi away from her terrible unrequited love interest. A-Zhu and her canonical fiance can stay friends instead (which works better anyway since said fiance is all but stated to be aroace).
Ode to Gallantry: Too much of a mess for me to take seriously even for crack shipping purposes. Also I don't think the two main female characters exchange more than a couple of sentences with each other.
The Smiling, Proud Wanderer: Ren Yingying intimidates me too much for me to suggest pairing her up with anyone else but the male lead, whom she's obviously deeply in love with. I could JUST about see pairing her up with Lan Fenghuang in a lady/handmaiden-but-with-poisons sort of way, but that would require a LOT of extra-textual imagination.
The Deer and the Cauldron: Can I ship the wives (except maybe Princess Jianning) with each other as one big happy poly family? And have them cut out Wei Xiaobao completely?
Sword of the Yue Maiden: A-Qing and Xi Shi (yes that
Xi Shi) A-QING AND XI SHI. I have a post-canon revisionist fic for this on the back burner of my mind; someday I may even write it.