Sure, here are some fictional characters that match the descriptions you provided:
- Empathetic, nice and gentle characters:
1. Atticus Finch from "To Kill a Mockingbird" by Harper Lee
2. Charlotte from "Charlotte's Web" by E.B. White
- Fictional character that likes science and is funny:
1. Sheldon Cooper from "The Big Bang Theory" by Chuck Lorre and Bill Prady
- Fictional character that is a nice and good helper:
1. Samwise Gamgee from "The Lord of the Rings" by J.R.R. Tolkien