Okay, I've been thinking about making a complete matchup list for a while, but I've been too lazy to do it. I've finally gotten over that laziness. Note that all these matchups assume that there are no customs on. The characters aren't in any particular order in each tier unless stated.
Without further ado, here it is:
Hypnotoad's List of Opinions Which Are Superior to Your Opinions
+3
Robin's best matchup. Ganondorf is the only character whose speed is comparable to Robin's, and who also has no projectiles. Robin can easily zone him out with Arcfire, and due to his heaviness, he is complete combo bait.
Slow, heavy, no projectile, combo bait.
Slow, heavy, no projectile, combo bait.
Slow, heavy, no projectile, combo bait.
+2
He would be a +3 if not for the fact that he has a spammable projectile to mess with your Thunder charging, and he has excellent recovery so he is difficult to gimp. His hammer also has very long range.
He would also be +3, but the long range from his sword and semi-decent speed make him a +2 in my opinion.
Although Marth is quite fast and is not heavy, there is very little he can actually do to Robin. His lack of projectiles means you can simply zone him out with Arcfire, and the massive nerf to his sword range that he received means that you can challenge him with your own sword.
Everything I just said about Marth also applies to Lucina.
+1
Slow, super easy to KO due to weight, doesn't have any projectiles, easily gimpable due to lack of an up B. However, she has a small model and cannot be comboed.
The matchup is similar to Marth. However, his sword has longer range, and he can turn into a mini-Sonic with the Monado Arts. There is a complete analysis of this matchup in the first post in the thread.
Large model, fairly easy to combo, her only projectile is pathetic. Watch out for the reflector.
Similar to Marth. However, he does have a projectile, albeit a bad one.
0
Although he has a reflector and a projectile, he also has abysmal recovery.
Has a decent projectile and a good aerial game, but isn't that big of a problem for Robin.
Has a non-spammable projectile and a reflector.
Similar to Jigglypuff, but is faster, stronger, has better recovery, and has a pseudo-projectile from Final Cutter.
Great aerial game, but no projectile.
This is an interesting matchup. At first, you might think Rosalina wins, because she can absorb your projectiles with down B, and Luma can sponge everything but Thoron. However, she is also light and easy to KO.
Has many projectiles, all of which are very slow and easy to shield.
Has a spammable projectile, but can be juggled due to the Levin Sword outranging her aerials.
Has projectiles, but is also slow and easy to combo.
-1
Fast, strong, can combo Robin, has a reflector, can mess with your recovery with the Cape and F.L.U.D.D., and unlike Dr. Mario his recovery isn't garbage.
Spammable projectile, can combo easily, great recovery.
Spammable projectile, good recovery, hard to punish.
Fast, spammable projectile, can combo, has multiple methods for recovery.
Fast, excellent recovery, can combo.
Spammable projectile, reflector, good recovery.
Fast, small, spammable projectile, can combo, excellent recovery.
Very fast, can combo.
Small, amazing aerial game, very good recovery, can absorb your projectiles.
Very spammable projectile, excellent recovery, reflector.
Everything said about Pit also applies to Dark Pit.
I have very little experience with this matchup, but from what I can tell, he has spammable projectiles, a good aerial game, and is small.
Spammable projectile, very fast.
Spammable projectiles.
Spammable projectiles.
Fast, can combo.
-2
Many, many, MANY spammable projectiles.
Same thing as Link, except now he's faster and smaller.
Once again, many spammable projectiles.
Spammable projectile, very fast, excellent recovery.
Small, amazing aerial game, can combo, can absorb your projectiles. Similar to Rosalina, except smaller and harder to combo.
Even better at zoning than you are, the Pikmin are super spammable and super annoying. Is also small and has very good reach with his aerials.
Spammable projectiles, can combo, has a reflector.
Spammable projectiles, small, can absorb your projectiles and throw them back at you.
This one might be somewhat controversial. While he doesn't have any projectiles, he also happens to be EXTREMELY fast and hard to punish.
-3
HOO HAH. Is impossible to punish, bananas can ruin your day, good recovery, small, amazing aerial game. Robin's fourth worst matchup.
Nairo thinks this is Robin's worst matchup, I think it's the third worst. Sheik has a spammable projectile which is also one of the fastest projectiles in the game. She is a very fast character, she can combo you, she has amazing recovery, she is impossible to punish.
Robin's second worst matchup. Has a spammable projectile, although luckily it won't interrupt a Thunder charge. Is very fast, can combo, has a reflector, can jab lock, is difficult to punish. Not a fun matchup.
Here it is, the character everyone loves to hate, and also Robin's number one worst matchup. Zareidriel thinks this matchup isn't that bad, but I have to disagree. He may not have a projectile, but he does have one thing that Robin absolutely hates dealing with: he's fast. The fastest character in the game, to be exact. You cannot zone him at all, by the time you throw out an Arcfire he's already in your face hitting you. He's also small, and can combo you. Sonic is an absolute nightmare for Robin.
So there are my opinions. Please keep in mind that these are opinions, not facts, and that they may not necessarily be correct. Feel free to agree, disagree, get defensive, call me a scrub, etc. If you want me to be more specific about some matchups, let me know.