Bones' Booth Always Carried Three Specific Items In His Pockets Throughout The Series
Temperance Brennan (Emily Deschanel) and Special Agent Seeley Booth (David Boreanaz) are better known colloquially to "Bones" fans as merely Bones and Booth. The two characters began the series as diametrically opposed figures, with Bones representing reason, logic, and empiricism, and Booth bringing more instinct, humanity, and belief to the table. Booth was a former Army Ranger and has learned to trust others in times of danger. He's also a devout Roman Catholic, giving him a lot to discuss with the devout atheist Bones. Booth was also a former gambling addict, something he talks about throughout the series. Naturally, Booth and Bones would develop a romance over the course of the show's many seasons, starting a relationship in earnest at the end of the sixth season of the show. By the end of the 12th, they would have two children.
Booth's gambling addiction would come into play in the show's 10th season when the character had a brief relapse. The fact that he is an ex-gambler is a large part of the show. It seems that Boreanaz — via an article in EW — was always careful to carry a pair of craps dice in his pocket while in costume, wanting to remind himself of his character's background. Indeed, the dice were one of three items that Boreanaz was always careful to carry in his pockets while in character. This was a character choice, of course, and the items weren't meant to be seen on camera.
Boreanaz also carried a brass Zippo-brand cigarette lighter in his pocket, which is a reference to Booth's time as an Army Ranger (Zippo famously makes a line of military-themed lighters).
Dice, lighter, St. Christopher
The craps dice were there to let Booth release nervous energy surrounding his addiction. While it's never obvious on camera, one can assume that Boreanaz would occasionally reach into his pockets and fiddle with the dice during his character's more nervous scenes.
The third item Boreanaz carried in his pockets was a St. Christopher medal, a symbol of his Roman Catholic faith. St. Christopher is the Patron Saint of Travel, and figurines of the Saint can still be seen sitting on the car dashboard of devout Catholics to this day. Christopher's visage also frequently appears on medals, worn by travelers. The story of Christopher's patronage comes from the legend that he offered to carry an infant child across a river, an act he committed safely. At the end of the journey, it was revealed that the child he carried was, in fact, Jesus Christ. Christopher can be seen carrying the Christ child throughout Catholic iconography. He's one of the more salable saints, and many adherents carry medals of him.
While this isn't a totem that Boreanaz carried on set, it's still a fun piece of trivia: according to the Hollywood Reporter, Boreanaz and Deschanel had developed a subtle code for when they were getting on each other's nerves. They were good friends off-set, but working together could get to be overwhelming, so when they felt like they needed to stay away from each other for a brief spell, one would send the other a can of Diet Coke. Deschanel doesn't drink Diet Coke, hence the message was clear. Boreanaz did this more playfully, though, than anything.