Just off the top of my head, but what skills did the S-Class ninja Sasori demonstrate, other than the creation and use of his Puppets?
Let's run through this.
Senno Sosa no Jutsu, an A-rank ninjutsu which he used to conceal/brainwash his sleeper agent Yura while a member of Sand's ruling council.
He explicitly demonstrates kenjutsu in his own right when he stabbity-stabs Sakura.
He makes the best poisons outright, and is a superlative surgeon to convert his body into an Eclipse Phase morph; that's shitloads of Medicine.
Thousand Hands Manipulation Force requires some heavy duty fuinjutsu to rig up in his puppets, let alone the storage seals for his Red Secret Technique and other tools.
Then there's Human Puppets, which is some freaky freaky(unexplained) stuff.
Seriously, the guy was Ninjutsu 5, Taijutsu 4, Genjutsu 4 for a good reason.
What about Konan? Did she ever demonstrate any techniques that weren't based around her Paper Release specialty?
You mean Konan the woman with Yang, Earth, Water and Wind release?
That we only ever see fight once in the manga?
What skills does Kabuto demonstrate that aren't related directly back to his specialty in Medical Malpractice?
Fuinjutsu, as used on Anko to drain her post-timeskip.
Genjutsu powerful enough to nuke an entire stadium during the Konoha Invasion. Ninjutsu powerful enough to use Edo Tensei. Summoning.
Fuckmothering Sage Mode, which Orochimaru was unable to attain.
And that doesn't include intangibles, like the skill to blend undercover in every major village in the Elemental Countries before he became a teenager. Or the combat ability to eliminate entire ANBU squads silently, or to lead forces against Kakashi and Gai during the Invasion.
Don't ever make the mistake of thinking Kabuto a one-trick pony.
Oooh, ooh, what about Naruto himself? How broad, precisely, is the training we see him receive?
Taijutsu Naruto, up to and including frogfu.
Wind Release Naruto. Fuinjutsu-summoning scroll Naruto, who had the skill to create Sage chakra channeling clones and link them to a scroll.
Sensor Naruto from Sage training.
The only thing we don't see him training in or using is genjutsu, and we see that cost him when two successive Uchiha get inside his head.