Native speakers: Does this sound natural in English?

Yeah that's normal

Yep, sounds formal but it's completely natural in english

Sounds fine. I'd be more likely to say "anyone who knows me knows I've always been a big fan of the late Laura Branigan" though. It sounds a smidge more natural to me.

sounds good

Sounds good.

Normal. Of course different people have slightly different opinions on Greatness.

Yeah. I'd even go so far as to say this sounds incredibly neutral. Anyone could say this in virtually any context

👍🏾

Looks normal.

It's sounds natural, but it's very formal. More casual would be: You know me, I've always been a fan of Laura Branigan.

I would consider it natural. I would probably say "*you'll* know I've always...", but

Funny to see all the different variations to express this same sentiment. While the OP's sentence sounds absolutely fine to me, I'd be more likely to say "If you *knew* me, you'd know I've always....."

Sounds fine.