He is fairly easy to get the basics of, as his kit is very straightforward. He also has a bunch of fancy combos to straight up delete most squishy targets while making his own escape. The changes to Stealth made it so Talon is 100% invisible aside from turrets (and the Sweeper's Outline or Oracle's in ARAM) with his Ultimate, further supplementing his safety even more. The downside is him being melee he CAN struggle against champions that will abuse him, however his farming is extremely easy with Rake (W). His Assassin's Path (E) makes his mobility top-notch and nigh uncatchable when retreating. He's currently the leader in First Bloods as well. He's an Assassin at heart, so you'll likely need to snowball and be able to have proper positioning to maintain relevance throughout the game and be able to delete squishies mid to late game.
Far more difficult than Talon and most other mid laners, Ekko excels at being a hyper-diving burst AP Carry with the ability to reset himself back in time to a previous position and save himself from ganks/tower damage/poor positioning. He has one of the most infuriating escapes to deal with, being able to push R and restore his own health, while simultaneously putting himself in a better position (although predictable), AND dealing massive amounts of damage to nearby targets. His wave clear is top-notch at level 1, push Q -> ??? -> Profit. He brings an AoE stun if you're able to set it up that combines into a shield for himself (scaling with AP) further allowing him to dive even harder to push his advantage. His Phase Dive (E) makes him very deadly with a Protobelt and Lich Bane, as he can close the gap from half a screen away and deal massive amounts of damage, almost guaranteeing his Passive will go off with Q to chunk out the opponent for ludicrous amounts. He is very difficult though without a fair amount of practice, so I would suggest against Ekko compared to say, Morgana, Ahri, or Xerath.
Everyone's waifu. She brings massive sustain with her Passive if you time it well into a large group of minions/enemies, True Damage with her Q, long-range safe CC to guarantee her combos with Charm (E), and has (for all intents and purposes) 3 Flashes/Dashes in her Ultimate that deal a minor amount of damage to nearby targets. She's incredibly difficult to lock down, and can easily turn around a gank while keeping herself safe. She's very straightforward with only a small amount of combos (E -> Flash animation cancel being the main highlight), however she scales fairly well and can easily delete squishy targets and make a quick pick in the late game. She is a straight-line skillshot style champion (similar to Ezreal) so if you're uncomfortable with this I would suggest others.
Typically seen in the Support role nowadays, Morgana packs a surprising punch with a small amount of AP. She has some of the highest AP Ratios in the game on her abilities, and crushes most AP Mid Laners with her Black Shield and raw numbers. She doesn't bring an escape, however her Passive (free Spell Vamp!) lets her stay in lane for a long time, while a few points in her W (Tormented Soil) allows her to nearly instant-clear waves faster than most any champion early. She's not very mechanically intensive, with her most common/flashy move being R -> Zhonya's Hourglass for AoE team damage/slows/roots, however she doesn't exactly need to be. If you land a Q on a squishy target late game, they are almost certain to die to your damage alone.
Holy crap get this guy away from our towers. He is an absolute monster at pushing out waves and by far and away the best tower pushing champion in the game. Left alone at late game with towers, he will take an entire base in under 30 seconds, effectively ending the game himself. He only has a few very small combos (mainly W -> mid-air Q/E/Auto and what-not), however he clears waves EXTREMELY well from a very safe distance. He's also very annoying to deal with for most mid laners, as only someone like Xerath can stay at such great distance from his Q and maintain wave-clear/harass. His mobility is limited to hitting the W to escape, so against someone like Hecarim who ganks you and pushes you off of it, the ability falls short most of the time. His Ultimate is wonderful for instantly clearing waves from a massive distance to protect your own towers, or executing enemy champions that think they're safe. He's also very difficult for lower MMR players to play against as his Q is a very awkward projectile with an AoE effect that is often underestimated. Your E provides a sometimes difficult to see zone that deals fairly decent damage and catches lots of enemies by surprise. Think they got a free last hit on your Twitch while they run through your mines? The tides will quickly turn against them.
The walking turret. Seriously can't stress enough how frustrating it is to play against Xerath for most laners. While he doesn't have any escapes on his own, he doesn't exactly need them as he is an entire screen (or more) away killing your carries. His damage ratios are absurd if you're able to hit a full combo, and his Ultimate allows you to clean up fights very easily (similar to Jhin) if you're decent at hitting opponents with the rather small AoE hitbox. If you have a Rylai's, however, you can almost guarantee to hit nearly every shot on your opponents (although this is more of a buffer at that point).
Hope this helps! There's plenty of other champions that do well in mid lane, however these (with the exception of Ekko and possibly Talon's combos) are fairly easy to get the hang of and transition your lead while simultaneously being able to farm with ease to maintain a steady gold income you can use to further push yourself ahead.