In the 1970's there were a lot of places that did not cancel their cards. Some places used ink stampers and defaced the face side with their name. About the only other type of canceling in the 1970's was drilling, occasionally you would see a cut corner or a notch in the side of the deck.

In the late 80's you started seeing what I call a shaved corners (probably actually cut), the cut is on opposite corners (i.e. Top Right, Bottom Left).

In the last 10 years I have been seeing a lot of cards which I call "Pinch Cut" where a 1/3-1/2" semi-circle is cut into opposite sides or top and bottom.

I would say drilling or cutting/shaving corners is what you mainly see being done to cards nowadays.

Where I work we probably destroy over 2/3 of our cards with an industrial shredder. We sell or give away the remainder (we notch one side). Some markets such as Macau are required by law to destroy all their used cards (I wrote the gaming authority in Macau to find out the law). There are also a lot of tribal casinos that have rules written to destroy all their used cards.