It's a bit odd how relatively forgotten MangaPokShipping is, any Advenutres related shipping discussion or fanart I see is usually RedxYellow or RedxBlue/Green/Leaf (with the latter being the more popular). RedxMisty virtually never enters the conversation.
I don't think it's that odd. The thing is Misty's possible romance has been getting attention since Gen 2 while Yellow's possible romance has been getting attention since Gen 3. Adding to that the difference in chemistry and character interactions is quite enormous. Yellow essentially met Red as a childhood friend and set out to rescue him not to mention the fact that she teamed up with Red at the very most I can think of... four times I believe? She teamed up with Red in the Yellow Chapter I think during the final battle, during GSC's final battle, during FRLG's final battle and during Emerald's Final Battle. In fact the reason why Kusaka, the writer of Pokemon Adventures, probably gives Yellow's relationship with Red more attention then Misty is simply because Yellow has the benefits of a main character. Her relationship with Red is much easier to do in a big story than Misty who is more of a supporting character as most Gym Leaders usually are. In fact Misty's interactions with Red has mostly been during the Team Rocket Chase in Mt. Moon, Cerulean City where she invited Red to her home, at the beaches of Fuschia City where she helps Red in getting across the water and talking to Red over the PC and at the end of GSC chapter alongside Yellow. Misty's interactions with Red are great but they are certainly small compared to Yellow's.
However keep in mind, this is probably also my own bias to be honest. I myself ship Red and Yellow together and believe that they should be one day be canon together! In fact it's probably my favorite ship. Shoz999 is the name. Favorite ship, Specialshipping. Favorite moment? There's a lot of favorite moments from that ship. The time Team Rocket teased the two about being a couple, the time Yellow had the courage to take off her hat in front of Red who had a hilarious shocked look on his face when he finally realize he was hanging out with a girl this whole time, the time Red held Yellow in his arms showing off his abs lol, their hinted ship leading to an entirely new canon ship called PikaChuChu shipping where their two Pikachu's start a family, Blue (Female Protagonist) teasing Yellow about living with Red like one big family lol twice with Misty at the scene... but my favorite moment of this fairy-tale-esque ship is none other than the time Red first met Yellow in the Viridian Forest, showing how amazing and friendly Pokemon are. I freaking love Specialshipping!
BUT! If I had to choose a favorite moment from MangaPokeshipping... it would definitely have to be the time Red and Misty teamed up together against Team Rocket. It's definitely one of those moments that grabs your curiosity if Red and Misty teamed up more against villainy rather than working on separate faraway locations like they later do in the Yellow and GSC chapters.