Even though he's still a nasty villain, King Koopa cares for his kids quite a bit. Special mention goes to "Mush-Rumors" when he's determined to keep his kids safe from the "aliens" after seeing Kootie Pie cry.
He also puts aside his feud with the Mario Bros. whenever it's one of his kids' birthdays, staying in his castle all day to shower them with stolen presents.
In True Colors, he places Cheatsy and Kooky on his lap and pats them both on the head (just not before making sure there's no one around to see him do it).
Toad bringing the wrestling tournament's prize money to the orphanage in "Tag Team Trouble"... even though they already had the money they needed.
Meta-example in "The Venice Menace," in which the Italian language is made up of nothing but names of famous Italians and Italian-Americans. One of the names uttered is "Lou Albano", AKA Mario's old actor/voice actor.