Yes, there are likely many out there. You can start by looking on popular fanfiction websites like Archive of Our Own. Just search for 'Jessie Luke and Jessie kiss' in the search bar, and you should be able to find relevant stories. However, the quality can vary greatly, so you might have to read through a few to find one that really suits your taste.
One possible plot could be that Jessie and Luke are friends who gradually develop deeper feelings for each other. They might go through some adventures together, face some challenges that bring them closer, and finally share a kiss in a moment of realization of their love. For example, they could be working on a project and start to notice little things about each other that they find endearing.
Jessie is an important character in Toy Story. She's a toy with a lot of energy and enthusiasm. She has a backstory about being abandoned and then finding a new family with the other toys.
The relationship can be developed through shared goals. For example, if they both aim to capture a super - rare Pokemon, they could work closely together. Giovanni could provide Jessie with better resources and training, which would make Jessie more loyal to him. Another way is through a backstory. Maybe they both had a difficult childhood related to Pokemon, which could create a bond between them.
James could be a potential character in Jessie's harem. They have a long - standing relationship in the Pokemon series, and in this fanfiction concept, it could develop into something more within the harem dynamic. Another could be Butch, as he is also from the same villainous group and might have an interesting relationship with Jessie in this new context.
No, it is not appropriate. Writing adult fanfiction about a character like Jessie can be disrespectful to the original work and its intended audience. Fanfiction should generally be in the spirit of creativity within the bounds of good taste and respect for the source material.