That was a fascinating article, Linda!
I remember my parents saying that, when they went to Greece many years back, their tour guide was attempting to tell the group that the bus would be leaving for the next destination in 5 minutes. As she was holding up the correct number of fingers, she very swiftly switched so that the back of her hand (rather than the palm) was facing outwards. She remembered just in the nick of time that to hold up one's hand palm-outward, in Greece, was about the equivalent to saying "feck off" to anybody who could see it!
I tend to think of all the gestures I use as "usual", but perhaps they aren't to other members here.
Not Rude
Making a circle with the thumb and index finger - "OK"
Making a "V" with withe index and middle fingers - "Victory" or "Peace"
Making a fist with the palm upturned and index finger extended... then curl the index finger towards yourself - "Come over here"
Index finger raised, palm outwards - "Wait one minute" or "Just a minute"
Thumb, index and pinky fingers raised - "I love you" (Ameslan)
Index and pinky finger raised (one or both hands) - "Rock on"
Rude
Making a fist, palm inwards, with middle finger raised - "butthole" (though ruder)
Drawing a circle at the side of your head with your index finger - "You're crazy"
There are probably many more rude signs that are slipping my mind, but I'm not in the habit of using them, so they don't stand out in my memory.