Hrmmm... A lot of them are gonna depend on the setting, honestly. But there are a few good character questionaires out there. Personally, I like to use roleplaying games as a guidance tool. You could go more specific and have a 200 question thing to fill out, but RPGs that ask these kinds of questions tend to give you enough of a structure to figure out a bare minimum and you go from there. You could go D&D 5e simple:

What is my name?
What is my lineage?/What culture did I grow up in/Who is my family?
What are my skills/abilities?
What do I apply these skills towards/How did I acquire them?
What are two brief statements that define how I interact with people generally?
What worldview drives me?
What are my personal goals?
What flaw do I have that can get in the way of relationships?
What relationships do I have outside my family?

You could scale back even further: Describe myself in 5 words or less, 3 things that define me beyond my core, a trouble that regularly affects me and my relationships, and my skillset. That's the FATE Core set of questions.

There are other systems out there, and there are questionaires out there that don't assume a game. But even if you don't think Sammy would be a good D&D character, the questions that D&D asks of you at their core are still good questions to consider.

Well the thing is, Default Sammy is kind of a normal person with out special powers or weapons or fighting ability or anything. I have thought of doing an AU Dungeons and Dragons version of him, but the problem is that I'd need to figure out who he is first as a regular person.

Still, appreciate that you put this here.

Oh yes, notice that the questionaire didn't ask about your *class*, however. Even if you're not an actual D&D adventurer, you still have skills, you still have a profession. That's why I pivoted from 'Class' to 'Skill and Abilities' as part of the question set ;) It gets at the heart of what's being asked of you: What is it that you do?

Also, the FATE Core questions don't even necessarily assume you're a D&D adventurer, merely that you are a protagonist in whatever story you're in, which is why I included it as an example ;)

What are two brief statements that define how I interact with people generally?
What worldview drives me?

I don't understand these 2 questions. Got an example of answers?

(styled after Personality Trait and Ideal as part of D&D 5e's Backgrounds)

"I've never really grown up. I'm basically a big kid."
"I can get lost in my work and become forgetful"

"Perseverance: Never give up. Never, never, ever give up. Where there's a will, there's a way"