Bloodlines - S7-E22
Continuity mistake: When Jason and Picard are having a conversation in the holodeck, Jason says "I remember her telling me about all the boys and girls who didn't have anyone to care for them" while looking in the opposite direction of where Picard is sitting. The camera angle changes to a close-up and Jason now has his head turned slightly towards Picard.
Visible crew/equipment: Boom action is visible in reflections on computer consoles in the back, while Picard and LaForge talk to each other on the bridge. (00:40:15 - 00:40:46)
Visible crew/equipment: In the opening scene when Data is portraying a character from Shakespeare's play "The Tempest" a small card can be seen attached to the back of the book he is carrying (likely containing his lines), but after increasing the amount of torch light the card is no longer there.
Continuity mistake: With his right arm Data is accessing the holodeck circuitry via the manhole while he is holding back a taxi cab with his left arm. Each time the scene switches to viewing Data from the back you see his right hand in the manhole and eventually his left hand appears. All the while you still hear the sound of the taxi cab. Each time the scene shows Data from the front he is holding back the taxi cab with his left hand.
Other mistake: When the ship is at max warp and Geordi states that at maximum warp the ship can only sustain two hours of emergency life support, Data, Troi and Worf are on the holodeck attempting to stop the train, but back in the bridge before they do you can see the view screen in the background and the bridge glass dome above Geordi, Picard and Riker that the ship is not moving at warp speed and is at standstill.
Continuity mistake: When alien party arrives, the turbaned assistant puts down the carpet roll the wrong way round. The next shot it is miraculously switched around so it can be rolled out towards Picard.
All Good Things... (1) - S7-E25
Character mistake: When Picard jumps to the past, he meets Data for the first time in engineering. If you look at Data's uniform, he is wearing the rank insignia of a Lt, Junior Grade.
All Good Things... (1) - S7-E25
Other mistake: When Picard first meets Data in the past, Data's rank insignia is wrong. He's always held the rank of Lieutenant Commander, signified by two gold pips, and one with black in the center. However, Data has one gold, one with black, signifying Lieutenant.
All Good Things... (2) - S7-E26
Visible crew/equipment: Captain Picard joins the poker game and Data asks the Captain if he wants to deal. Picard says "Thank you Mr. Data." Riker sits down, and just before Captain Picard starts saying "Actually..." a camera or other bit of equipment briefly pops into shot behind Riker.