Bro forgot about the goat......Crash Nebula

Somewhat interestingly, my favorite psudo-example of this is Digimon Tamers, which was a soft reboot of the Digimon anime that treated Adventure and 02 as an in-universe anime and card game.

My favourite "anime within an anime" is Lucky Star season 2, which gets a fake-out intro in the Lucky Star spin-off The Miyakawa Family's Hunger (Miyakawa-ke no Kuufuku).

To date, there's no actual Lucky Star season 2 so the fake-out intro sort of counts.

Anime within anime is a concept I feel like isn’t explored to its fullest potential. It kinda just gets reduced to generic jokes about how strange otaku are or something.

Hmm… maybe I should check out these shows you talked about!
I’ve been meaning to watch some anime again anyway and these look right up my alley!

Being a manga/ anime about cosplay, My Dress up Darling has a good few of these in universe properties. A couple anime with Flower Princess and We’re the Tsukiyono Company, a couple manga with The Student Council President is the no. 1 Host, Succuprob, and Mandate of Heaven, and a couple games in Coffin and Slippery Girls. I’d honestly watch or read a couple of these

Magical Girl Bunny Girl with adorable talking floating animal mascots is 100% the kind of series fundamental that would sell me.
...wait isn't this basically Friendship is Magic but with less characters

I so thought that My Dress-Up Darling would have been a main contender in this video.

Despite having no memory of watching it or Genshiken, I always feel happy when Kujibiki Unbalance is mentioned.

Seeing King the baby lion from Nadia and the Secret of Blue Water as a fake anime character inside another anime was a surreal experience

As a guy who is currently watching Mazinger Z, Gekiganger looks like what you remember as you childhood, animating (and looking) better than it actually was, even if I did not experience Mecha anime back when I was a kid. It's like I'm imagining what I would have remembered those 70s robot shows looking like if I had actually grown up with them, if that makes sense.

I don't know how it would work, but now I want to see you collab with KaiserBeamz.

Lack of Celestial Being the movie is a grave mistake.

funny you mention Fat Albert (the live action) but not the og cartoon...which did, in fact also have a show in the show the gang would watch, 'The Brown Hornet' which itself was a parody of the Green Hornet but in space.

In 1988's Gunbuster, which takes place in 2023, there's a poster on Noriko's wall advertising that the 1980s' biggest rock act, Van Halen, apparently went on tour again in 2021 for an album called "I Only Enjoy What I'm Doing."

Eddie Van Halen died IRL in October 2020. RIP.

Fun fact about Otaku no Video, all of those interview segments are skits. They're not real they're mostly played by the staff who worked on the anime though we don't know all of them since it's uncredited, however, one person we DO know the identity of is the Otaku who was obsessed with the hentai game and that guy was played by none other than Hideaki Anno

One of the more humorous take on the subject was with "First Love Memories" in Welcome to the Demon School Iruma-kun. It starts off as your typical romance manga, with the classic trope or a girl clashing with a boy. But then it escalated into sheer lunacy as the characters get themselves into weird and weirder scenarios. (At one point, the male lead literally go to space, for crying out loud lol)

In-universe, it's depicted as a popular manga, spanning a ton of volumes. So some people do wonder if it only got that far because of the sheer insanity the story. It also has a tie to out titular lead, Iruma-kun, as he was once an assistant artist for the manga.

Re:Creators was done dirty... it died the same way Titanfall 2 did, it got sandwiched between massive shounen hype drops and was buried.  If it came out in a more quiet period it would have been the talk of the town, and one of the new huge things.  Re:Creators should have been huge (and consequently gotten continuation) but it wasn't... it's so sad.

I always had a feeling that Re:Creators have the same premise as Jack Slatter from Last Action Hero who come in the real world in the third act of the movie but it's the whole show. That's the thing who give me interested for this show.

An interesting inverse example, I think, is the way 'Girls und Panzer' uses actual war films. The characters watch old live-action classics like 'Kelly's Heroes' in order to get pointers for their tank strategies, and we get to see clips from these in animated form. So, animated versions of real live-action films, made in our world, but being watched in 'GuP's insane tank-obsessed alternate reality. Very interesting.

So more of an Anime within a Game, Pure White Lover Bizarre Jelly from No More Heroes always stood out to me.  It might be partially due to the fact that the Director Suda51 had floated the idea of potentially turning it into an actual series, and if you know anything bout Suda, it'll be a wild ride.