
Necromancing the Stone - S5-E21
Visible crew/equipment: When Piper hits the mirror after being thrown across the room by the energy bolt, look closely at the roof in the other room: a black rectangular hole with a stage light poking out of it is visible.

Continuity mistake: In the beginning when you see Piper and Paige sitting in the car talking on their cell phones, Paige has hers in her right hand. You can see she has a ring on one of her fingers. In different shots the ring is gone. (00:00:30)

The Power of Three Blondes - S6-E4
Continuity mistake: When Phoebe gets a phone call from Elise, Phoebe's phone changes back and forth from her right ear in the wide shots to her left ear in the closeups. (00:18:45)

Other mistake: During the second attack on Wyatt, when he lets his force field down the top of head is transparent from the special effects.

The Truth Is Out There... and It Hurts - S1-E8
Revealing mistake: When Phoebe asks Piper what she thinks of her boss, you can see that Holly's tattoo has been covered up, because that part of her wrist is darker than her skin. (00:17:15)
Suggested correction: Maybe Holly covered it up with makeup because she isn't supposed to have tattoos for her job? A lot of jobs still don't allow piercings and tattoos today but all those years ago it was even harsher.
There are multiple instances of covered tattoos during the early seasons. I noticed it the most on Alyssa's back tattoo.

Love Hurts - S1-E21
Continuity mistake: When Prue shoots the Darklighter arrow at Alec, he orbs out and the arrow sticks into the wall behind him. In the next shot, the arrow has disappeared. (00:25:45)

Continuity mistake: At Phoebe's high school reunion, the gym teacher holds out a name tag in her left hand, but then Paige takes it from her right. (00:07:50)

Continuity mistake: When Prue leaves Buckland's, she's wearing a red tank top, but when she arrives at Camp Skylark, her shirt is different, both in style and color. She can't have stopped to change, because it's mentioned she left the auction house and headed directly to the camp. (00:07:00 - 00:09:20)

Visible crew/equipment: In the scene with Chris and David in the attic, a boom mic dips into the shot. (00:28:50)

The Importance of Being Phoebe - S5-E11
Continuity mistake: When Kaia, pretending to be Phoebe, holds up the document from the bail bondsman, it jumps from her left hand to her right. (00:33:20)

Wrestling with Demons - S3-E12
Continuity mistake: When Phoebe finds the lost and found spell for Piper, the paper the spell is written on moves relative to the top of Phoebe's keepsake box. (00:10:30)

Continuity mistake: When Paige is trying to convince Piper and Phoebe that she needs to save Larry's soul, she has the Book of Shadows open to the page on vampires. In subsequent shots, the open page changes to two different demons; but Paige's hands are down by her sides the entire time, so she couldn't have flipped the pages over. (00:26:35)

Magic Hour - S3-E2
Visible crew/equipment: When Prue and Phoebe see Piper arrive home, a boom mic dips into the shot. (00:01:30)

Continuity mistake: When Phoebe tries talking to Emma about Belthazor, Emma's hands are folded in front of her, holding her sweater closed. In the following shot when Emma turns around, her arms are now down by her sides, with her sweater open. (00:31:10)

I've Got You Under My Skin - S1-E2
Continuity mistake: When Phoebe flirts with Alec at Quake, she rests her head in her hand. In the following shots between Alec and Phoebe, her hand moves back and forth from her face to the tabletop. (00:02:00)

Wicca Envy - S1-E10
Continuity mistake: At the beginning of the episode when Piper hides her sisters from Leo she has the shirt with the buttons closed, but between that scene the shirt is not closed. (00:01:05)

Continuity mistake: When Paige is telling Glen the evil enchantress story, her hand suddenly appears under her chin. (00:01:15)