@Heather225 I have no favourite one. All are unique in their own way.
Fictional characters that come into my mind who might be on the autism spectrum:
Dr. House, Sheldon Cooper from The Big Bang Theory, Eru Rōraito and Nate River from Death Note (anime).
A list of real people who might be(en) on the autism spectrum can be found here: https://www.appliedbehavioranalysisprograms.com/historys-30-most-inspiring-people-on-the-autism-spectrum/. Actually I'm not very happy about labeling people with diagnosis since I don't have the full picture and sources aren't reliable.
My favorite autistic character is Forrest Gump as an autie who I can relate to in so many ways, next to Sheldon Cooper as both of them have an eidetic memory.
I remember a movie i liked named Cube (1997), where appears a character with autism, but i think It was very exagerated
The character of Sam Gardner I thought was fairly well done. Since the character was designed as having the diagnosis, it's a little less of a trope than something like Sheldon Cooper and more complex than Raymond Babbitt from what I remember (although it's been a long time since I've seen the movie). I like Shaun Murphy too but I think Sam's characteristics are a little more representative whereas Shaun's are more to fit the storyline. If going more for the trope I would pick Temperance Brennan as a favourite. I read quite a few of the books well before the show though and I do feel like the tv character is quite a bit different from the book character, and I much preferred the books and don't recall them fitting the trope so much, but it's been quite a while.