Blythe's friend Sue admires Blythe a lot and in episode 7 she comes off as a Stalker with a Crush towards Blythe by copying everything she does, right down to the shampoo.
Penny and Pepper go on quasi-dates in "Penny For Your Laughs". At least in Pepper's mind, that is.
Sunil and Vinnie seem very close to some viewers. In "Blythe's Big Adventure Part Two", during the fashion show, Vinnie helps Sunil out in showcasing one of his magic tricks, probably due to Sunil's huge Performance Anxiety. After Sunil saves the day in "Gailbreak", Vinnie comes up to him and gives him a big hug, and in "Russell Up Some Fun", they team up to prank Russell while giggling like a bunch of girls, and Sunil laughs heartily about Vinnie's Incredibly Lame Puns afterwards.
At the end of "Lights, Camera, Mongoose!", Vinnie goes to check if Sunil's alright (like he did with Penny earlier). Sunil is so happy about being back in Littlest Pet Shop, he pulls Vinnie close and their noses◊ bump together◊.
In the same episode, Vinnie basically had a mancrush on Shahrukh, another mongoose that looks very similar to Sunil.
Take a sip everytime Sunil and Vinnie cling to each other for safety in "Door-Jammed". They also do a Thriller parody where the two are in place of Michael Jackson and his girlfriend. Finally, it is also interesting to note that they accused all the other pets of being werewolves... but not each other. They also seem to spend time watching horror movies together.
Sunil's Imagine Spot of being a doctor and operating on Vinnie (who lost his tail) goes from him playing real music instruments in the operation room (which results Vinnie into getting a peacock tailof all things), to Russell, Minka and an overjoyed Vinnie fawning over him. Watch it here.
In "Eight Arms to Hold You" the two embrace each other out of reflex, notice and awkwardly let go of each other. During the episode Vinnie also keeps falling on Sunil as a Running Gag. When Sunil falls on Vinnie one time, he's happy things are "finally going his way".
Minor example; In one part of "Eight Arms to Hold You" Vinnie asks Sunil to "rendezvous" in the hall at night to crash Blythe's party together. Sunil asks him about the meaning of rendezvous, and Vinnie acts perplexed. Since it can't be that he didn't know the meaning of the word as he used it in the correct context, did he realize the romantic connotation the word can carry?
In "Heart of Parkness", Vinnie appears to be the one worrying the most about when Sunil got lost in the park. Since he volunteers to be the lookout on the boat, hoping he can spot Sunil.
In "A Day at the Museum" Sunil and Vinnie get excited about watching a horror movie together. The being touchy with each other and hugging in fear from "Door-Jammed" makes a come-back.
In "Blythe's Big Idea" they are taking a bath and goofing off in a tiny tub of soap water together. For the Pet Jet fantasy, they are seated next to each other just like a couple would be and hug once again in fright when they suspect they are going to crash.
In "Commercial Success", they are sitting on the same chair while watching Jasper's commercial.
In "Shanghai Hi-Jinks" there's a brief scene at the start where Sunil pats Vinnie's head and affectionately calls him "sweet, ignorant Vinnie". Upon hearing they are going to Shanghai, Sunil lifts Vinnie up and swirls him around. At the end of the episode Sunil specifically goes to Vinnie, lifts him up again and hugs him, while praising him for his "colossal footwork" while dancing. None of the other pets do that with Vinnie. Their expressions really sell how much they like each other◊.
As of "Sunil's Sick Day", the writers aren't even hiding it anymore.
Though seems to be averted in "The Expo Factor", in which Sunil falls madly in love with the cat Delilah. This could either be the writers stamping the Ho-Yay out, or Bi the Way.
They briefly hold hands in "Sleeper", and Vinnie's line while he's doing it can take on a whole different meaning out of context.
Vinnie: We can't let anyone know about this!
In "Tongue Tied", Vinnie got all emotional by Sunil's speech.
"The Very Littlest Pet Shop" takes this up to eleven. After the Pet Shop and pets are shrunken, Sunil gives a scared Vinnie a soft reassuring shush, and starts stroking him to calm him down. Even further when you find out the entire shrinking adventure was simply a fantasy Vinnie was having, think what you will of that. Then again... in fantasies the pets tend to interconnect their thoughts, and usually aren't figments of one single pet's imagination, (so unless Vinnie was imagining independently and the others simply watched as he was zoned out), Sunil may have been the REAL Sunil.
Zoe Trent and Pepper Clark basically have a lover's spat in "Dumb Dumbwaiter".
In "Frenemies", the two once again get into an argument on which party theme is suitable for Penny Ling. They make up by telling each other how great they think the other is.
In "Blythe's Big Idea" Blythe specifically takes Youngmee along with her when searching for a kiosk and while going shopping together they are shown holding hands.
The song "My Biggest Secret" from "The Secret Recipe" about Blythe deciding whether she should tell Youngmee about her ability to talk to animals could easily be taken out of context so she's confessing something else.
Not only that, in the song Blythe gives Youngmee numerous Longing Looks and it's shown how much she loves spending time with Youngmee. And then the scene where Blythe imagines Youngmee getting to know her secret [of being able to talk to pets] where Youngmee holds Blythe's hand and meets all the pets (who all love her) all while Blythe is looking so damn happy about the whole situation. And at the end of that fantasy Blythe imagines Youngmee looking at her with an adoring look.
In "If the Shoe Fits" Blythe and Youngmee walk into a party holding hands◊ the way a couple usually does.
In "Helicopter Dad", a scared Russell leaps into Vinnie's arms in Minka's Fantasy Sequence. In the same episode Minka's affection for Olive Shellstein resembles a crush.
In "Door-Jammed", Whittany and Blythe seem to get friendly fast after being stuck in the bathroom together, and it's revealed that Whittany actually likes Blythe a lot, she just treats her poorly because Brittany doesn't like Blythe.
However, this plot point isn't brought up at all throughout Season 2, and the Biskett's schemes seemed to be their nastiest yet (especially in the Expo two parter where they go out of their way to sabotage Blythe, such as disabling Mrs. Twombly's vehicle to make her late to the expo, getting their butler to lure Blythe away from a scheduled photo shoot by holding a fake one, and then stealing Blythe's stand and claiming it as their own). Time will tell if Whittany still secretly likes Blythe, or if the writers ended up dropping it and had her go back to sharing her sister's opinion of her.
It's questionable if this even counts as Ho Yay, because at this point it seems to be canon, but Vinnie's crush on Bruce the Iguana in "The Big Feathered Parade". Vinnie is completely infatuated with him, calls him his hero and daydreams about dancing with him on the parade while red flowers fall from the sky. Zoe even teases him about him having a "reptile crush" on Bruce, with Vinnie smiling after that comment.
In "A Day at the Museum" Minka and Penny Ling raise a baby dinosaur together and call it MinLing.
At the end of "Shanghai Hi-Jinks", Minka hugs and clings to Penny's face in her joy.
In "To Paris with Zoe", Madame Pom kisses Zoe numerous times on the cheeks upon reuniting with her.
Also when Zoe says she has a boyfriend, Madame Pom is shocked, she admits it's because she doesn't want Zoe to be distracted from the competition but it honestly looks like she feels threatened.
During their song about Paris, Sunil gives a flower to Russell near the end (much to the latter's appearent discomfort). This is particularly noticeable for happening not long after his fantasy number about dating a human woman, suggesting some interesting things...
Seems to be outright confirmed in "Secret Cupet", with Genghis and Tootsie who are shown as a romantic couple, but are both males.
In the first short, "TALE-RAVE-IUM", L-Zard and his gang of dancing reptiles make a come-back, and oh boy does the short ooze Ho Yay between L-Zard and Vinnie, such as L-Zard somewhat suggestively shushing Vinnie when the latter has self-doubts, Vinnie and L-Zard showing their dance moves to each other in what can only be described as a "gay dance-off" and Vinnie being absolutely ecstatic to see L-Zard dance.
Then comes the second short, "The Ladies of LPS", and it's almost as if it tried to be even gayer than the first one. It's chock-full of Les Yay mostly between Minka and the other girls, such as Penny and her jumping on fluffy hearts, and generally is about how much the girls like each other.
All of the girls: Leave the boys, it's time for girls!