It can be official, modified, or entirely homemade. What do you like about it? Is it super organized, simple and easy to use, or does it just look super cool?
The character sheet for the Mothership RPG cleverly has the rules for character creation built right into the sheet.
I’ve never played the game, and the sheets give me the sense that it probably wouldn’t be my cup of tea… but Eoris Essence’s sheets are beautiful in a way that most character sheets really aren’t.
Maybe not quite what OP had in mind, but I’m a huge fan of characters that are simple enough to be quickly recorded on just a sheet of notebook paper. Stuff like Maze Rats, Knave, or even some PbtA games. There’s something that feels nice about not needing a special layout to surface just the “important parts.”
Completely acceptable answer.
I’m a fan of the Ironsworn character sheets. They manage to make tracking a number of different sliders really easy and straightforward. And it is all a single sheet (plus some cards for assets). Efficient.
If we’re talking about D&D 5e, here’s one of my favorites. “So many activities! It’s making my head spin, how many activities we could do.”