I've only listened to a few episodes myself; I think osmosis will probably be enough to get you through.

All right, then! Let's see...

Merlin:
The Virtue, Chickens, and Destiny series, by Nyxelestia. 93K. The series is about Arthur, newly crowned, discovering that his loyal friends have (as in canon) been lying to him, and trying to build trust and forge a kingdom based on the truth, instead of the lies that haunted Uther's era. There's background Arthur/Gwen, but the relationship at the heart of the series is non-romantic and non-sexual Arthur&Merlin (the author marks it as a queerplatonic relationship). It's definitely one of my favourites. The first main work in the series is Tear the Lies Asunder: Starts after 'A Servant of Two Masters'. Arthur, worried about Merlin's excessive drinking and scars on his neck, starts trying to snoop around to see how he can help his manservant with whatever demons are driving him to the tavern. Instead, he stumbles across the webs of lies his friends are spinning around him. Heavy is the head that wears the crown, though Arthur had never needed to bear such weight on his own - but until he finds out what everyone is hiding from him, that is exactly what he'll do.

The Perfect Scry by DisaLanglois is a post-S3 AU where Arthur, upon finding out that Merlin can scry, comes to two conclusions: first, that Merlin has magic, and second, that Merlin doesn't know he has magic and must be protected from the truth. It's more serious than the summary makes it sound, though there are certainly some funny moments, and it's very good. I especially like the take on Arthur here, devoted to Camelot and his friends, but also willing to change his mind upon receiving new information. There's /very/ background Arthur/Gwen, and a moment that implies Merlin's in love with Arthur, but otherwise it's pure gen. 50K. The world is falling into winter. Camelot is falling into war. Arthur will do anything he can to keep his kingdom safe, and he will use whatever weapons are at hand - but, to his horror, his decisions turn out to have severe consequences for Merlin. Naturally, Arthur decides that it is his duty to protect his loyal servant from the shocking truth...

“Let me see if I’ve got this straight,” Lancelot said, beginning to grin. “You want to teach Merlin to use magic – without letting him notice that he’s using magic?”

“He must not find out. If he finds out he has magic, he’ll – why are you laughing? This is no laughing matter, Lancelot!”

Also by DisaLanglois, The best-laid plans. I think I'll leave the description purely to the author's own summary this time, but I do want to add that it's one of my favourite Merlin fics, it's often very funny, and it's purely gen. The best-laid plans of mercenaries and magicians...

In the aftermath of the rout at Ealdor, a mercenary leader tries to hold his small band of survivors together and extricate them from the mess he got them into. He thinks he’s come up with a simple plan to save them all, but things soon stop going according to the script. And then they meet with a group of knights, led by a knight who calls himself Sir Andrew of Dollop Head.

Arthur decides, for who-knows what reason, that he wants to spend his honeymoon chasing a gryphon all over Camelot. Merlin, as ever, is tagging along behind Arthur, but his usual plan of pretending to be a simple servant isn't working. Arthur has been behaving strangely ever since their return from Ealdor, and Merlin is worried. On the road, they meet with a small band of riders who insist that they are also Knights of Camelot, and Arthur comes up with a strange new plan all of his own...

Girl Genius:
Well Met at Mechanicsburg" by khilari and Persephone_Kore is a long-time favourite of mine, and probably the most accessible Girl Genius fic I can think of if you don't know the canon (though that's not saying much), since it's a pre-canon AU that ends up going in a different direction that canon and sometimes the kids in-fic need things explained to them. There is a romance, but it's really not the focus of the fic. 203K. AU. Never having concluded Klaus was working for the Other, Barry Heterodyne returns to Mechanicsburg just in time to interrupt the Wulfenbach takeover. As Barry and Klaus tackle Europa's problems and settle into their new responsibilities, Aaronev's plotting sends Tarvek to join Agatha and Gil in a new friendship that may disrupt everyone's plans. (If you end up liking this, the authors also wrote Jaegers as an Aid to Diplomacy" (gen) and the Agatha's Bad Plan AU (mostly so), and Persephone_Kore and adiduck wrote Correspondence (gen).

Finally, there's an MCU series, The Undone Universe by Teyke, which...I find nearly impossible to describe so I'm just going to quote my Day 3 rec:
"--I'm not even sure how to begin to describe this series. It's mostly MCU fic, but it diverges at the end of the Avengers and it's got a strong 616 influence. It's about 628K words. Each of the longer individual works forms a complete story in itself, nevertheless working to develop an overarching plot which ends beautifully. The beating heart of the story is the relationship between Tony and Steve; it's marked as gen but honestly the entire thing feels to me like a developing relationship which hadn't quite finished developing by the time the series ended. It's about pushing the boundaries of technology. It's about love. It's about doing what's necessary--and about working out what really is necessary, and what you might be tempted to think is necessary, in the moment. It's about compromise. It's about having a computer in your brain. It's one of my favourite things anyone's ever written, and it's great.

The first fic is called Saga, and I'll just give you the summary from the fic itself: Tony falls into the closing portal, but he doesn’t make it out the other side before it snaps shut. Trapped in a universe where time runs oddly when mortals blink, and accompanied by a Not-Quite-Dead Steve Rogers, Tony mouths off to a goddess of death, goes cross-dressing with Thor and Loki, and learns to hate Asgardian engineering. Oh, and he may have caused the end of the universe as they know it.

Highly recommended among all high recommendations."

I hope there's something here that you like :)