Newtina - 1, 2, 5, 7, and 20.
1- I would perhaps let them have a less antagonistic beginning. Though, I think the fact the do is very sweet. Just could be interesting if they met in a calmer state, rather then being at one another throats so quickly.
2- I love Absolutely Smitten by Dottie for Newtina. Just fits them beautifully.
5- Salamanders Eyes, of course! With their scene on the roof in the first movie as a close second. As well as their reunion in Kamas hideout.
7- I LOVE the idea of Tina tracing Newts freckles and Newt playing with her hair being just small bits of normal affection between them :). There are a lot more, but those headcanons come to mind first.
20- Funny story: I learned Newtina was canon AFTER I both read the screenplay and watched the movies. Started shipping them COMPLETELY blind. The moment they rally together to try to calm Credence is defiantly the moment I was 1000% on board with this ship. Just was the nail in coffin.