Here are the top-rated Rizzoli & Isles episodes according to IMDb

"...Goodbye"

Season five, episode two

In the midst of solving a murder, the detectives have to gather their thoughts, be strong and think of ways to express their sorrow during their final farewell to Detective Barry Frost.

This episode had a rating of 8.6, making it the highest-rated episode of Rizzoli & Isles throughout its run.

"Ocean Frank"

Season seven, episode 13

Series finales are always a big deal, and the one for Rizzoli & Isles was no different. In fact, it's the second highest-rated episode of the series on IMDb.

Korsak's retirement party is underway, and it was also Jane's last day. The department makes a farewell video as they gear up for their next adventure.

"When the Gun Goes Bang, Bang, Bang"

Season one, episode 10

In this hectic episode, an undercover cop is killed. The murderers make their way to the HQ for an invasion, seeking to capture evidence taken by Rizzoli. The detectives are trapped, and the situation eventually results in a shootout.

"Killer in High Heels"

Season four, episode four

What happens when Dr. Isles becomes the suspect in a murder case? This episode tests the partnership of Rizzoli and Isles, as Maura needs Jane to trust that she's innocent. However, Maura can't remember much of what happened and is arrested.

"5:26"

Season six, episode 12

Rizzoli is placed under protection after her apartment was set on fire by an unknown person. The mysterious individual also hacked her financial accounts and threatened her and those close to the detective.

"Remember Me"

Season two, episode ten

There's a special day mentioned in this episode: Rizzoli's birthday. As Maura can't decide what to give Jane as a gift, the two investigate the death of a young man killed in prison.

While they investigate, another prisoner, who had cancer, tells them the story of a cold case consisting of a family of four that vanished.

"Burning Down the House"

Season two, episode 15

In this episode, a warehouse fire claims the life of a firefighter. The detectives aimed to see if this was an accident or arson. Maura and her mom became the victim of a hit-and-run. While Maura only has a few bruises, her mom was seriously injured. 

"Hide and Seek"

Season six, episode 13

Isles is kidnapped from a fake crime scene in the middle of the night. The team does everything they can to ensure she's not harmed while also trying to find answers to "Who would do this?" and "Why would they do this?"

While in harm's way, Maura realizes that Jane is the target and that the kidnapping was a set-up to capture her.