The tri-color pairings are divided into two groups that, at least up until now, have been exclusive to set releases. The “arcs” are three colors next to each other in Magic‘s color wheel (below) and are related to the plane of Alara. The “wedges,” a color and the two opposite it on the wheel, are related to Tarkir.
Bant decks, with White as the central color, are all about harmony through control and strength. Bant is definitely warlike, but to further peace and order. Some other mechanics that Bant use are gaining power through community (as seen in the Exalted mechanic) or giving blockers ways to attack (Arcades the Strategist).
Esper, drawing from its central color Blue, is all about improvement at any cost. The end goal of Esper decks is to hold absolute control over all aspects of the game. A recent example of this is Chromium, the Mutable, a powerful creature that can protect itself from almost anything. On Alara, Esper had an artifact sub-theme, presented in powerful artifacts like Sharuum the Hegemon and Sphinx of the Steel Wind.
Black is the core color in Grixis, which is focused on the power of self and survival. Sometimes this means singularly powerful creatures like Thraximundar or one of the game’s iconic villains, Nicol Bolas. Grixis decks like to ask “how far are you willing to go to survive?” And the answer is usually “I’ll go farther.”
Jund decks follow their instincts, which tell them to destroy everything else. Brutal and powerful, Jund gets its way by aggressively crushing all opposition. Whether it’s with a powerful dragon couple, a goblin warband, or simple brute force, Jund comes to rumble.
Grounded in Green, Naya is about the power of nature. Naya has monstrous creatures like Zacama, Primal Calamity, but it also has the power to bring these creatures to bear, like with Godsire and Mayael the Anima.
Abzan cares about sustainability. Slowly grow bigger until you’re unstoppable. Powerful and flexible threats like Siege Rhino define this wedge. Of course, sometimes it also means cutting away your weak points, illustrated by creatures like Ghave, Guru of Spores.
Jeskai is all about being cunning, flexible, intelligent, and devious. Combos are often found in Jeskai colors and most of these decks benefit from casting a lot of cheap spells. Narset, Enlightened Master and Kykar, Wind’s Fury are exactly where you want to be.
Sultai is ruthless and seeks value out of everything. Most often, that involves abusing the graveyard. Load up on zombies using Sidisi, Brood Tyrant or bring things back from the grave with Muldrotha, the Gravetide. You could also simply seize control of the game with a card like Leovold, Emissary of Trest.
Mardu wants to go fast and get aggressive. Their cards will often push them toward all-out attacks like with Ankle Shanker. Make your attacks more impactful by taking out their best blocker with Crackling Doom or find a warleader with Kaalia, Zenith Seeker.
Temur is all about being savage. Particularly focused on creatures, Temur decks have powerful and multi-faceted creatures like Savage Knuckleblade and Animar, Soul of Elements. They also aren’t afraid to rely on tribal synergies or combos, most recently exemplified in Omnath, Locus of the Roil.