Prior to discovering D&D, probably my main source of fantasy (along with movies like Clash of the Titans and The Last Unicorn) was Mattel's Masters of the Universe toys, which debuted in 1982 (truly the annus mirabilis of my childhood pop-cultural obsessions).
As toys, they weren't that great - all of the figures had the same super-muscular body, just with different heads, paint-jobs, and accessories, and I believe they only moved at the shoulders and hips - I don't think you could even really turn their heads. Nevertheless, something about them really clicked with me. Loking back, I think it was the way that all of the initial characters were all primal, mythological archetypes, more like gods than people: He-Man was Hercules, all strength and heroism, Teela was magic and wisdom, Man-at-Arms was science and reason, Stratos was the air and the sky; on the bad-guy side Skeletor was the personification of death and evil, Beast-Man was primal rage and fury and fear of the woods, and Mer-Man was the dark depths of the sea and fear of drowning. None of this was articulated at the time (I was, after all, 7 years old), but I think it must have been floating around in my subconscious. Plus they all looked really cool - sort of a kid-version of Frank Frazetta, with big muscles and deadly-looking weapons and Castle Grayskull all darkly foreboding and mysterious. This seemed like a strange, dark, violent, and dangerous world.
Anyway, I really loved those toys, probably even more than my Star Wars and G.I. Joe toys. I especially loved the little illustrated storybooks that came with them that provided details about the characters and their world. There were apparently four of them initially, but the only one I remember was King of Castle Grayskull - I must have read that thing 100 times, and a lot of the pictures are still embedded in my memory decades later.
Alas, things went downhill from there pretty quickly. The second and subsequent waves of toys got more gimmicky with lots of moving pieces and increasingly lame concepts, like the guy whose head spun and had three faces - one good, one evil, one (?) - or various figures with spring-loaded fists, or (a particular low-point) a guy who was covered with fuzz and smelled like a pine-scented air freshener. The little booklets also changed - they became mini-comics with a different style of art and (so it seemed to me at the time) cheesier stories. I lamented that it didn't seem as cool and dark anymore, but stuck with it nonetheless.
And, of course, anyone who was a kid in the 80s knows where the story went from there. In the fall of 1983 the He-Man and the Masters of the Universe cartoon premiered and it was just lame as hell. He-Man was no longer a Conan-esque barbarian hero, but was the alter-ego of wimpy and effeminate Prince Adam (who was, literally, He-Man in a pair of pink tights) and his pet tiger was also a wuss, and there was some comic-relief "thing" in a floppy hat, scarf, and oversized shirt with a big O on it called Orko that made no sense at all, and all of the bad guys were totally hapless and goofy, and nobody ever got hurt and there was always an explicit moral lesson at the end. Of course all of this was totally standard-issue for 80s cartoons, especially those based on toy franchises, and a lot of people a couple years younger than me seem to have a strong nostalgic connection to this series, but it felt like a huge betrayal to my 9-year-old self. He-Man was cool - it was dark and violent and dangerous, and the show wrecked that and turned it into garbage.
Luckily, right about that same time I discovered a new outlet for my dreams of a dark and violent fantasy world in D&D - and then watched over the next few years as it too grew increasingly sanitized, kiddified, and lame. Which is how I learned as a kid that nothing good lasts forever, so you need to hold onto it and cherish it while it lasts. Live in the moment, and accumulate a store of great memories that you can look back fondly on later. Good advice for a kid dealing with changes to their favorite toy franchises, and (I'd suggest) for life in general.