Here's Starlight Glimmer, and with her childhood friend and fellow mage — Sunburst! :iconstarlightcuteplz: Sunburst Icon
Before she met Twilight Sparkle, Spike, Applejack, Fluttershy, Pinkie Pie, Rarity, and Rainbow Dash, Starlight had one very special friend since she was an adorable little filly. Living in Sire's Hollow, she and this talented Unicorn have been always been very close. They used to play board games, like Dragon Pit; they would practice magic and spells, and their parents always smothered them too often, much to their chagrin. The two Unicorns were perhaps the best of friends. They even dreamed of attending Princess Celestia's School for Gifted Unicorns together. Starlight Glimmer was very good at casting spells as a filly, while Sunburst knew everything there was to know about magic. But sometimes, not all things work as we planned…
One day, the two foals were playing a book-stacking game. When Starlight's move nearly caused the books to topple onto her, Sunburst saved her using telekinesis, earning him his cutie mark. As a result, Sunburst left for Canterlot and got enrolled into the School for Gifted Unicorns, leaving Starlight without a friend and with a fear of losing potential future friends. Feeling betrayed and abandoned, the bitter Starlight became convinced that cutie marks ruin friendships. So she went down her dark path, and 10 moons later, Starlight created a town, where ponies were taught that cutie marks cause disharmony, and that anypony having different degrees of ability makes others unable to be proper friends. Then, she would proceed to strip everypony of their cutie marks, and place equal signs on their flanks. Fortunately, the Mane Six exposed her dictatorship, and she was forced to flee. Wanting revenge, Starlight used Star Swirl’s time travel spell to change history in order to destroy the bond of the Mane 6, unaware of the horrible consequences her meddling left behind. Twilight Sparkle, who she and Spike were sucked back in time, learned how important their friendship was to the peace in Equestria. Twilight showed Starlight this, but Starlight revealed to her and Spike her tragic story. Before Starlight could continue with her revenge, Twilight offered her hoof in friendship and taught her the importance of uniqueness and individual talents. Starlight finally accepted friendship, and then, Twilight took on the reformed Unicorn as her student to learn the Magic of Friendship.
Sometime after that, Twilight received very special news — her older brother Shining Armor and his wife Cadance had a baby! She and her best friends were invited to witness the newborn foal's Crystalling. Twilight also learned that Starlight's foalhood friend, Sunburst, was living at the Crystal Empire too, and decided that a reunion with him as Starlight's first friendship lesson. Starlight, however, was nervous about the reunion. Since he attended Princess Celestia's school, Starlight thought Sunburst was now an esteemed wizard, and he probably wouldn't take her past crimes very well. Nonetheless, she traveled with her new friends to the Crystal Empire. Starlight expressed her concerns about meeting up with Sunburst again, but Twilight was so preoccupied with her duties for the Crystalling that she didn't listen and instead delegated overseeing the reunion to Spike… with a very long list of steps. Upon arrival, the Mane Six followed Shining Armor to see his and Cadance's new baby girl, while Starlight and Spike set off to find Sunburst. Despite her attempts of avoiding the reunion such as getting Spike to gloat about his heroic status in the Crystal Empire, Starlight and Sunburst finally meet again for the first time in ages. Unfortunately, it turned out awkward and unsuccessful. Sunburst bragged about his status as a wizard, leaving Starlight intimidated and forcing herself to leave with Spike, dejected. While Spike offered Starlight reassurance that they were still friends, they learned that the new baby princess, Flurry Heart, shattered the Crystal Heart as a result of her uncontrollable magic, and the Frozen North's arctic storm besieged the Empire. When Twilight and Cadance are unable to find a spell to repair the Heart, Starlight rushes back to Sunburst, hoping he could find a solution. However, he admitted that he was actually a failing student; although Sunburst is very knowledgeable about magic, he is untalented at casting it. This gave a tearful Starlight the courage to admit her past shortcomings. Realizing that they both made mistakes, Sunburst apologized for losing touch with Starlight and not telling her the truth, and Starlight forgave him, and they finally have a healing reunion. The realization also gave Sunburst the confidence to quickly find a solution! When everypony returned to the Crystal Palace, Sunburst proposed carrying out the Alicorn baby's Crystalling and combining it with spells from Starlight, Shining Armor, and the princesses. With Twilight busy casting her magic on the Crystal Heart, Shining Armor and Cadance appointed Sunburst as the ceremony's Crystaller. As Twilight, Starlight, Celestia, and Luna casted their magic on the Crystal Heart, Sunburst, Cadance, and Shining Armor carried out the baby's Crystalling. The light and love within the Crystal Ponies channeled into a single crystal, which Sunburst then merged with the Crystal Heart. The resulting magical burst restored the Heart and dispeled the arctic tempest. Starlight commended Sunburst for coming up with the solution to the Empire's crisis, and Princess Celestia expressed her delight that he was finally able to put his unique gifts to use. Some time later, Starlight Glimmer and Sunburst finally rekindled their friendship and agreed to stay in touch.
Since then, Starlight and Sunburst would see each other. However, while Sunburst was visiting Starlight in Ponyville, she discovered that they didn't have anything in common like they used to, and that he did with Starlight's other friends, like Twilight, Trixie, and Maud Pie. Starlight worried that if she had no common bond with Sunburst, then they couldn't be friends anymore. When he realized how left out Starlight felt, Sunburst organized a life-sized version of their favorite board game for them to play together. He and Starlight agreed that they can still enjoy each other's company without having much in common. And they still do, especially with their new friends. And of course, they still had to deal with their doting parents when the Cutie Map sent them to their hometown of Sire's Hollow. At first Starlight's father, Firelight, and Sunburst's mother, Stellar Flare, were at each other's throats. Firelight planned on preserving the village's history as the head of the Sire's Hollow Preservation Society, while Stellar Flare was trying to revolutionize the village and promote tourism as the head of the Sire's Hollow Development Committee, and thus they would get into heated arguments. Eventually, Firelight and Stellar Flare realized how carried away they got with their respective efforts, they agreed to work together on a single vision that best befits Sire's Hollow. While Starlight and Sunburst set out to find the real friendship problem, Firelight's constant doting and Stellar Flare's overbearing concerns about her son's future caused the two friends to explode at their parents in anger. Starlight and Sunburst realized the real friendship problem was their strained relationship with their parents, and they made amends.
In time, Princesses Celestia and Luna announced their retirement from royalty, and Twilight and her friends were to rule in their place. Twilight delegated Starlight to be her School of Friendship's new headmare. Starlight struggled to find a vice headmare, and trying not reject Trixie for the position, despite her being hopelessly unsuited for it. But eventually, Starlight decided to not give Trixie the job despite her favoritism. Fortunately, Trixie suggested on hiring Sunburst as vice headstallion, seeing how he is perfect for the job, and Starlight offered Trixie the position as the school's new student counselor. And to this day, Starlight Glimmer and Sunburst continue working together as best friends, and it has been implied as a couple… but that's another story.
Not exactly the first MLP group pic on Eclipse I had in mind, but this will correlate to an idea I had in mind. Originally, I wanted Starlight Glimmer and Sunburst flipped from right to left, but I decied otherwise.
Starlight Glimmer by me
Sunburst by me
This is only the first of Starlight Glimmer with her other friends. Be prepared to see more, and with something special to come.