Not that I know of

I think the closest I've come to doing that is buying a bag of the Cardi B Honey Drip Rap Snacks.

and I don't regret it

YES. This one. https://youtu.be/4qSYbRSgyPI
It’s the secret to my shapely hips and thighs.
😏

Not that I remember, but my roommate and I both listen to Nicole Byer's (comedian) podcast where she does funny ads for stuff. My roommate's on a mission to buy all the stuff she endorses tbh (a Quip toothbrush and Native deodorant so far)

Not that I remember, sorry, to the contrary usually. I find products with much celebrity pushing rather annoying. But I tend to avoid advertisement. When I'm watching telly I tend to record it, cut out the ads and then watch the resulting 20 minutes, lol.

Sorta.. Depends on wether or not you consider YouTubers "celebrities"? The host of Binging with Babish suggested "better than bouillon" was (as the name suggests) better than bouillon and the next best thing to freshly made chicken stock. So that's what I buy now.

Yes, Steve Cram, Start cereal in the mid 80’s.