In Best Gift Ever, Minty Bubblegum is also the Mystery Mouseketool.

In The Lyra King, Minty Bubblegum is shown to have her very own Handy-Dandy Notebook. According to Dolly, she first got it in The Best Road Trip Ever.

@Nency Dermawan  
Here are some more quotes from Minty Bubblegum.
 
“This is the first time we’ve played Blue’s Clues in years! Oh, I feel so happy.”  
-Minty Bubblegum, The Lyra King (2019)
 
“I… think I have to get my OWN notebook.”  
-Minty Bubblegum, The Lyra King (2019)
 
“Dora, are you okay?”  
-Minty Bubblegum, Unikitty the Explorer (2019)
 
“But if Minuette knows ne,  
I know what she’ll do  
She’ll love me at once  
The way she did once upon a dream”  
-Minty Bubblegum, singing Once Upon a Dream in Lyra Heartstrings: Mistress of Beauty (2019)

In The Secret Diary Switcheroo (the adapted version of Applejack and the Honest-to-Goodness Switcheroo), Minty Bubblegum is one of the contestants in the Sweet Apple Acres Pie-Eatin’ Extravaganza. And in Daring Do and the Forbidden City of Clouds (the adapted version), since she lives in Tomorrowland, her role is changed from greeting Mr. Brown to being given some toys from Mayor Mare. This time, her line parodies her only speaking role in My Little Pony:
 
“I… think the Night Timer needs me. Gotta go!”

Minty Bubblegum’s design is different in Sundae Sundae Sundae. In the short, she looks like Applejack instead of Lyra Heartstrings.

In Best Gift Ever, Minty Bubblegum is voiced by Andrea Libman, as always, and only has one speaking line.

Quotes from Minty Bubblegum:
 
“Anything’s possible if we use our imaginations. Right, everypony?”  
-Minty Bubblegum, An Adventure in Make Believe (2017)
 
“Merry Christmas, everypony!”  
-Minty Bubblegum, A Hearth’s Warming Adventure (2017)
 
“Oh, it’s sort of thrilling to go trick or treating!”  
-Minty Bubblegum, Treehouse of Horror 3 (2018)
 
“Um, Spike, how can we get to the Ballet?”  
-Minty Bubblegum, Big Ballet Day (2019)

Minty Bubblegum first appeared in On Your Marks, and has the same mane and tail style as Amethyst Star, Lyra Heartstrings, Diamond Mint, Blooming Harvest, Lemony Gem, Rose, and Silverspeed, and the same tail style as Royal Ribbon. She is voiced by Andrea Libman.

I bet this character is a palette swap of Lyra.