Heart Pirates

The Heart Pirates are an infamous and notable rookie pirate crew discovered on the Sabaody Archipelago around the time the Straw Hat Pirates arrived there. Their potential is further seen with the release of Haki by Silvers Rayleigh, upon which nearly every notable crewmate save one were not affected.

Pirate Flag
Like many other pirates from the North Blue, the Heart Pirates do not use a skull and crossbones, but a smiley instead, possibly symbolizing the "Age of Dreams". Strangely enough, the protrusions encircling it resemble those of a schematized virus.

Known Crewmembers
The most prominent feature of the crew is that they all wear the same boiler-suit apparel, other than Law himself. The clothing design has also been seen worn by the Tenryuubito and their slaves, with the only difference being that the Heart Pirates have their Jolly Roger on their suits. At least 5 crewmembers including Trafalgar Law and the newly recruited Jean Bart have been confirmed. It appears that Bepo and the two unnamed members are all proficient in martial arts, of which they all seem stylisticly similar.

Crew Strength
It can be presumed that they are a strong crew for them to have made it all the way to Sabaody Archipelago with only 4 members at most. With the addition of the new member, famous pirate Captain Jean Bart, the crew may have grown even stronger. All crewmembers were able to withstand a blast of Haki from Silvers Rayleigh.

Trivia

 * Law's Jolly Roger bears some similarities with Doflamingo and Bellamy's Jolly Rogers, although one should note that Doflamingo and Bellamy's Jolly Rogers have a cross over them.