Mainly the drag from side of the net, waiting for the goalie to drop, and putting it top shelf short side. Our team doesn't have enough people to field defensemen and lots of teams have used that shot against us when we only have 2 forwards, including the game winner in our 2-1 loss in last month's playoffs.
I understand the whole "play better defense and they won't be able to do that shot", but when you have 2 players on your team against a team of 3-4, there's no way to stop the cherry pickers who only try that glitch. Especially when it goes in like 75% of the time.
For the record, I love teams that only know how to cross-crease. That is not a glitch, just good hockey. It's also incredibly easy to defend against.
The other (arguable) glitch is the drag/top-shelf shot from the top of the circle against a CPU defenseman on a 1-on-1. I don't really think it's a glitch goal but others do. I think it's a combination of terrible CPU defense coding and the goalie not being able to see the puck behind the defenseman's legs. It's also pretty easy to defend against if you play a solid 2-way game as a forward.
edit - my description of the side of the net glitch goal was pretty terrible and sounds like a legit goal... the glitch is when a guy drags from the top of the circle off the side of the net all the way to the side of the net ~1/2 way from the boards, then curls toward the goalie at the goal line and top shelfs it when the goalie fails to react. It's like a 1-3 second hold on the drag until the goalie fails to react then shooting
edit 2 - I found a youtube video of basically how it works, but with a left handed forward attacking on the right side.
NHL 12 - Goal Line Curve Shot Glitch - YouTube It's pure cheese and lots of elite teams have used it against us in the past