Seconding the love for Bonnie!!! Her dynmamic with her brother, as well as the cute, sister-like bond she has with Serena, us so adorable...
Iris!! I love her tomboyishness, her big brown eyes and round cheeks (cute!!), her pastel outfit, her sarcasm, the way she teases her friends, but absolutely has a heart of gold and cares deeply (the Deino episode ;___; the way she cheers Cilan up after hurting his feelings, making up with Ash after a fight, her and Ash sightseeing in Nimbasa all day...).
She has a temper and she's very motherly to Axew, she loves nature, and is spiritual...
Her dynamic with Cilan is also so cute!! Reminds me of childhood ships like Hanawa x Maruko and Rocketshipping: I love blunt, sarcastic, tough tomboys and upperclass, charming, pretty-boys with more luxurious tastes...
Shootie/Trip!! He might not be written much like a main rival for Ash, but he's a very unique character, and the way they slowly start to become friends by the end and work really well together in a pinch is sweet!!!
I love the royal/noble theme of his team, his voice (in the original, more), design (the asymmetrical haircut's pretty unique!), his sarcastic and aloof nature, the way he has to prove he's so grown-up (which Iris uses to trick him into battling Ash like, twice, PFFT), and the fact he can be very kind (wouldn't take advantage of Oshawott's fear but helped Ash notice it, offered to help Iris with her phobia, protecting Castelia, etc.)...
His ends justifies the means mentality in the Venipede episode
But also that he was very expressive and shy and, honestly, sweet as a younger kid. His Alder fanboying is adorable. The biggest thing that makes him totally different from Paul is the reveal in the Junior Cup
Lillie, I often gushed about, but also, she's especially dear and important to me since (abusive/neglectful/narcissistic mothers are still rare in media, she had trauma-induced memory loss, and I also loved cats from afar after getting scrached as a little kid (still have the scar!), and when I had overcome my fear, my first indoor cat was a Persian cat named Snowy [named after Snowene, Kimba's mother], can't make this stuff up, I've got pictures and a webpage I made as a kid as proof).
She's just too sweet and endearing and you can't help but want to cheer her on!! Her smile makes me feel like my heart's so full, it's gonna burst! She's perfect. ;___;
[attached, one of the tumblr posts I gushed about her in, reblogged elsewhere, since my original blogs are all gone.]