I can think of a few I had in the past and recently.
Trish vs Lita: I didn't know who was more ticklish back then, or even if they were ticklish. But knowing how ticklish Trish is compared to Lita, I'd say Lita would win.
Carmen Electra vs Pam Anderson: They were both tickled on The Howard Stern Show. Howard is considered a bad tickler, but Carmen still reacted more than Pamela, and as even admitted to her feet being extremely ticklish; her most ticklish stop. So, Pam would win this one.
Mickie James vs Melina: Both have admitted to being ticklish. Mickie being very ticklish on her feet, sides, and neck. Admitting she would lose if tickling were legal in wrestling in a Cameo DM. Melina being so ticklish it hurts, pedicures tickling, her dog licking her feet tickling, getting violent when tickled, and hating being tickled. Both seem really ticklish, but Melina seems more ticklish, so Mickie wins.
Paige VanZant vs Paige(Saraya): Both have been tickled multiple times and are confirmed very ticklish. Paige has had her feet tickled by her BF twice, once purposely, and once accidentally when he licked her toes. She also had her feet tickled by Airwrecka and could barely handle it. Paige(Saraya) had her feet tickled by her BF twice, feet tickled during a fish pedicure, feet tickled in a wrestling match, feet tickled by her dog(lickle), and tickled by Alicia Fox on her armpit. They both seem equally ticklish, but VanZant's MMA experience edges her out.
Rihanna vs Nicki Minaj: Not as much information as others. But Rihanna has admitted getting her tattoos really tickled, while Nicki had her toes tickled by her BF. I guess it would depend who gets who first. Rihanna has a massive size advantage, so I'll give it to her.
Ronda Rousey vs Natalya Neidhart. Ronda has never been seen tickled, but she's admitted many times of being violently ticklish. Natalya has admitted to being very ticklish when getting massages, and has been tickled on a YouTubers channel, and had her feet tickled by her sister twice. Similar to Vanzant vs Paige, Ronda's MMA/Judo would seemingly give her the advantage, but her extreme ticklishness could leave her defenseless, so I give it to Natalya.
Alexa Bliss vs Becky Lynch. Like Ronda/Natalya, not as much information. Alexa has been tickled by her BF, and has admitted that pedicures can tickle, so I'd say her feet are above average ticklishness. Becky has only been tickled on her armpit once, which she reacted admittedly. Becky has the size advantage, and if she's only ticklish on her armpits, she could take it. But, given that's extremely rare, I say Alexa would pull this one out. Especially since her little hands could get in a lot of places.
Torrie Wilson vs Stacy Keibler. I was always surprised WWE didn't have then tickle each other, at least once, during one of their many Bra & Panty matches. Torrie has admitted to being very ticklish on her feet and sides, and becomes more ticklish the longer she's tickled. Stacy has never confirmed to being ticklish, but she was tickled on her sides on DWTS, and her feet one time during a massage. I'd say Stacy wins since Torrie has the unfortunate disadvantage of becoming more ticklish the longer she's tickled.
Nicki Bella vs Brie Bella. Both have confirmed and rate their ticklishness, and how ticklish they are from their neck to their feet. Nikki has never been seen tickled, but she has tickled Brie, and she's very ticklish. Brie has also admitted she would lose to Nikki in a tickle fight. Being Brie's admission, and Nikki being more of a ler, Nikki beats her twin.
Mandy Rose vs Sonya Deville. Mandy has admitted to being ticklish, pedicures being ticklish, and even being tickled by Sonya. While Sonya has admitted to absolutely hating being tickled. Being she hates it so much, that could lead to an early loss where even her amateur MMA background wouldn't save her. She seems like a ler that hates being a lee, so I'd say Mandy taps her out.
Rhea Ripley vs Bianca Belair vs Raquel Rodriguez. 3 powerful women who are as ticklish as they are strong. Rhea was tickled by getting a massage, and told a story of when her BF tickled her and she lifted him up to escape the torment. Bianca is terrified of being tickled, and admitted to pedicures tickling, Raquel was tickled while getting muscle therapy and was clearly on the higher end of the ticklish scale. Bianca's fear of being tickled might lead her to bow out sooner, leaving Rhea and Raquel. Rhea has already shown she has the strength to fight out of being tickled, and Raquel is very weak to tickling, so I think Rhea reigns supreme in the end.
Darlene Ortiz vs Jennifer Lopez. Darlene is very ticklish, so ticklish on her feet she does her own pedicures. Jennifer Lopez has admitted to hating being tickled, especially light touches as Leah Remini showcased, she has been tickled on her sides on Monster in Fall, and had her feet tickled on Angel Eyes. If Darlene is has ticklish on her feet as everywhere else, that could be a problem. But with JLO having such a dislike of being tickled, she could give up a lot sooner.