Hmm...there are probably others, but off the top of my head:
Rayquaza and Sky Attack/Hurricane/
Brave Bird: Probably the one issue that has annoyed me the most. It's the freaking
embodiment of the skies in Hoenn legend, and it can't learn either of these moves! I've been waiting for Game Freak to fix/rectify this issue (particularly with a Sky Attack Move Tutor in
Pokemon HeartGold/SoulSilver, and nothing came about!) Even non-Flying type Pokemon like Ulgamoth/Volcarona and Whimsicott can learn Hurricane! You would think the Japanese names for Sky Attack and the English/Japanese names for Brave Bird would cause "issues/discrepancies" with their 'avian'/'bird' terminology, but that's not the case, since Crobat, a,
bat, can (at least in Generation 5) receive both Brave Bird as a bred Egg Move and Sky Attack by Move Tutor!
Victini with V-Create as a Level-Up move: The move seems designed specifically for Victini (what with the "V" motif, and the
Pokemon anime even seems to encourage this link), but the availability of this move has been restricted to events only, and only Victini and Rayquaza can have it in a legal moveset...
Zangoose and Cut: With its prominent claws, it can Slash and Fury Cutter all it wants, but it can't cut down simple (roadblock) trees? Its name even uses the Japanese term for "cut". At least this Pokemon has a visible rationale for learning Cut, unlike Diglett (currently)...
Zekrom and Drill Liner: Its TURBINE TAIL conveys a "drill" motif in my opinion, so the move would be quite fitting. Alas, it can't learn it. And although the move description involves the user "rotating its body like a drill", Rapidash can learn it (probably because of its horn) even though I imagine that horses would have a hard time actually rotating their bodies like drills. If liberties can be taken for Rapidash, why not Zekrom? On a side-note, I wouldn't mind Zekrom learning other drill-based attacks like Horn Drill, Drill Peck, and Megahorn in the same vein.
Zapdos and Hurricane: Apparently the only Legendary Bird of Kanto that can't learn it, a move that would be much more viable than Drill Peck as it runs of Zapdos' naturally high Special Attack.. WTF? Zapdos is a
thunderbird and all, and hurricanes seem to fall in line with thunderstorms, mainly regarding the "high winds" aspect..
Zapdos/Articuno and Air Slash: I don't know why, out of Kanto's Legendary Bird trio, only Moltres can learn this move.. Articuno's case seems even worse; if you can cause destruction on par with a
hurricane, you should be able to "slice" through air
easily.
Reshiram/Zekrom, post-Generation 4 starter Pokemon, and the move Earthquake: Really, anything heavier than Diglett (yes, I know it's a Ground type which probably explains its usage of the move, but still) should be able to learn the move. Even the non-Ground-type/mineral-related Wailmer and Wailord (the latter of who, mathematically, should be less dense than
air) can learn Earthquake, so the substantially heavier-than-air Reshiram and Zekrom should be able to learn it, too. Also, the fully-evolved Unova and Kalos starter Pokemon look capable of causing Earthquakes, so I don't know why the 'tradition' of having fully-evolved starter Pokemon learning Earthquake was abandoned beginning with Generation 5...
(Mega) Blastoise and Shell Smash: Everything with a shell should be able to learn this move, no excuses... I'm wondering if (Mega) Blastoise would be overpowered, though...?
(Mega) Ampharos and Tail Glow: One of the most glaring omissions where a Pokemon can't learn something that matches
several Pokedex entries.. At the very least, give it Nasty Plot so I can
pretend that it has Tail Glow.. >_>
Frogue/Greninja and Rapid Spin: This rumored combination seemed to be eagerly anticipated by fans before it was proven to be nonexistent/untrue in
Pokemon X and Y, although I would like to see how it would be implemented without being overpowered..
Blaziken and Bounce: It can take skyscraper-sized leaps, so why not?
LOTS OF THINGS AND NASTY PLOT: Lots of things would benefit from a sizable Special Attack boost, so I would love to see Nasty Plot receive more distribution.
Tyrantrum and Head Smash: Oh, hey, it exists?!
Lots of Pokemon without Fly: I'm willing to suspend my disbelief for the nonsensical implementations...if it flies
somehow, the Pokemon should be able to learn this.
Flygon and Brick Break/Dragon Dance: It would be
really more useful in Hoenn's Battle Frontier and elsewhere if it got a break and received a decent Fighting-type move or stat booster..
Serperior and Dragon Pulse: Contrary Serperior with Leaf Storm's inverted stat drops would work wonders with the move. Dragon Tail only just doesn't cut it.
Lati@s and any Fire move except Hidden Power Fire.
Seriously.: I was quite shocked when I found out that these mighty Dragon-type Pokemon can't learn Flamethrower
and/
or Fire Blast. That's just a disgrace among Dragon-type Pokemon, man!
Here we talk about Pokemon that you think should have a certain move, but doesn't.
I'll start off: Gengar and Nasty Plot. How does Gengar not have this move? It seems like a perfect fit for Gengar's mischievous personality and its sizable Sp. Atk.
This (although maybe overpowered?).
Why Can't Druddigon or Scyther Learn Fly When They Obviously Have Large Visible Wings?
Yet You See Golurk (The 700 Pound Chunk of Metal and Rock) Flying With Ease Throughout the Skies.
Dodrio Can Learn Fly As Well (Despite the Fact That Its Based on a Flightless Bird and Has No Wings) Maybe It's Heads Function Like Propellers On a Helicopter and It Spins Them Around to Fly?
What About Mew? The Floating Pink Cat? How Does That Manage to Fly?
Or Perhaps You Were Wondering How Genesect Learned Fly? Perhaps It Reverses Its Blaster and Launches Itself Using It Like a Jetpack.
Well With This Logic You Would Think Girafarig Could Learn Fly, or Maybe Dugtrio?
Lol XD
It Is Clearly Shown That Druddigon and Scyther Have Wings, So Why Can't They Fly?
This. Mew has an exception via gameplay, I guess, but still!
Inkay line doesn't get any Water moves barring Rain Dance, even though they are based on squids which is clearly an aquatic creature. It kinda surprised me when I found that out.
And I agree with Kyurem lacking Ice Fang, if the other Tao Trio dragons got their elemental fang move, why couldn't Kyurem? It would have helped Black Kyurem's physical attacking prowess way better.
This.
Why doesn't Flareon get Solarbeam? Literally every single other fully-evolved Fire type has access to it, but not Flareon.
Also, why can't Starmie learn Calm Mind? Generally Psychic types can learn it, yeah? So why?
And then there's the matter of Unfezant and Brave Bird... you're going to give it a massive Attack stat, but not access to the best physical Flying move besides Sky Attack? Really?
There are a bunch more, but those are the only ones I can think of off the top of my head.
This (although for some reason, I'm indifferent to Flareon receiving Solar Beam; I'm just glad that it FINALLY received Flare Blitz in Generation 6!).
Gyarados and Crunch. Seriously, you make his Mega-Evolution part Dark type, and his only move to get STAB off it is Bite? Have you seen Gyarados' mouth? Pretty sure he can Crunch.
Fearow and Brave Bird. I mean, Fearow is a bird, right?
Gallade and Sacred Sword. Absol and Leaf Blade. And this is only a small fraction of the list.
This, excluding Gallade and Sacred Sword. I hated that a legendary-exclusive move got distributed to non-legendary Pokemon; the Honedge line is enough for me.. >.<