Do you have your "pikachu" pet?

[Nythiz]

Tamed Snarler (Black Lean Wolf/Coyote look) in Ferelas waaaaaaaay back when pets had different stats, and his was particular OP at the time. Still have him to this day, going by the name of Askani.

Same, only mine's named Zero

Loved the Black Coyote look, and even back in those days (Vanilla/TBC) you didn't see many people with the snarler skin. Most seem to favor the worg looks.

Have him since Vanilla, I've used him less since Garou (WoD), and later Hati, set a new benchmark for cool wolf pets.
But if I ever had to chose only 5 pets from my stables to keep, I think Zero/Snarler would be the only non-special pet that makes the cut

[The Cheat]

My hunter still uses the grimtotem spirit guide that they let us keep after fixing the trick that let us tame it. Doubt I'll ever not use it.

[Knight Meta]

My Stabled has with little exception been filled with nothing more than Rare-Unique pets since the inception of my Hunter back in Cataclysm. Yet during mid Cata I tamed the Silithid Colossi simply named "Hive Controller" since I had seen no one use exactly that model before + he had a root and I did mostly PvP. I aptly named him Buru (Because I am that Original) and when people asked where I got him I kind off just lied and said "Idk man, Buru just entered this state" - As I keept using him and hung out outside SW for many hours a day, doing duels inbetween BG ques; Buru became a bit infamous due to him being a "Ugly ass pet with an annoying ass root" - Yet I loved the bugger and grew fond of him.

Years have passed and while many of my old pets has been replaced over the years due to the loss of their Rare-unique status; Buru still remains and is always in my 5 ready to go loadout of pets.

[Stabbyfists]

Back during Vanilla (not Classic) I had the elite panther pet I trained from Stranglethorn Vale however, she got deleted and I got served a 30 day suspension.

I affectionately named her Hctibelttil and someone reported me and I got a month long ban and when I logged in, she had either gotten deleted, or ran away. I was devastated and quit my lvl 45 hunter that day. I rerolled mage and never touched my hunter "Lycoris" ever again. I miss my little panther.

[The Butt Witch]

Gon

Not only it's a spirit beast, so it has the utility and stuff, but also its model is the largest raptor pet in the game. When you tame a pet, its model shrinks down by 33% or something, so it will always be smaller than mobs of its type. But Gon's model doesn't, so it will always be as big as a mob model of its type.

[MatthewOU2015]

My wolf from cata. Never gonna abandon him

[Motso]

I did. It was this weird little bird pet from the orphan event that was an egg with a birdy head and legs sticking out. I think he was named eggbert and at one point he could 100% pull aggro when he would run up to enemies.
He disappeared from my pet roster at some point a long time ago and I have never bothered caring about pets since.

[khazlol]

The spirit fox from duskwood has been at my side for years. was a pain to find and tame.

lightning paw for those who care.

[Beet]

Yep I’ve got my Broken Tooth from vanilla on my hunter still to this day. I refuse to get rid of him. He was basically THE go to pet for pvp in vanilla as he was the only pet with such an absurd attack speed, 1.0 exactly. It was like fate that the moment I got to Badlands my buddy was telling me to keep an eye out for him because of how great he is and sure enough on my way to Kargath I see him. I ran over and tamed him with immense excitement. Right as I was taming him I had a mage rushing over to try to kill it but I got the tame off and killed him.

I miss those old days. Classic is a lot of fun but nothing compares to that feeling you had as a newbie in World of Warcraft.

[Rehija]

Still use Lok Nahak as my prime Pet in Retail. Back then i leveled in Sholozar when i dinged 78 and not a minute later he spawned right in front of me. Guess it was fate

[Twen]

After finishing the belf leveling area I went to Silverpine forest and tamed a black worg, named him Lucius because that's the name I got in my head when I looked at his face. When I was big enough I asked help from a tank friend and got a saddled version from the start of Hellfire Ramparts and kept the name. Years and years later updated to a more recent model. Always by my hunter's side unless the situation requires something specific.

[buck008]

I didn't start maining my hunter until Wrath. I grabbed one of those grey/white wolves from Storm Peaks and named him Santos after the episode of the Simpsons where Bart gets a credit card in the dog's name. Santa's Little Helper became Santos L Halper. Much like you guys, I get all the new fancy pets, rare spawns, unique looks, whatever I happen to like. But one space always stays for Santos.

[Lei]

My hunter had a Mazzranache named floyd for the longest time.

It's called McNugget in my stables.

I remember when pets used to give stats. My stables is full of "Speedplz" KingsPlz", StatsPlz", "HastePlz", "StaminaPlz", "RessPlz" and named alike pets. Many of them nothing special but can't let them go. Probably should.
My pikachu pets are probably Echeyakee that I got on my first ever wow char, an alliance hunter, my friend leveled a horde char up to 16ish to get the quest and the item to summon him. And then the original rare white gorilla, called Gouryella (yes, after the music band).
Nowadays I run with a fel green core hound because that matches my hunter's transmog (gladiators chain armor), but still very much attached to Echeyakee and Gouryella.

[DazManianDevil]

I have Shy Rotam from BC, back when she was a summoned quest mob in Winter Spring.
I was level 60 and she took a very long time to tame, nasty habit of breaking my freeze traps and fearing me and killing me.
Good times!

[Mokenuf]

My hunter has a wolf, one of those you can tame in Hellfire Ramparts. I've got it since late TBC/Early LK.

[3DTyrant]

Wilson, my armoured ghost boar from RFK (or was it RFD? One of the two), he's my oldest pet and he's been with me for years.

[Mighty Parrot]

So I guess my future new "pikachu pet" will be Elegon. Yep. The sparkle dragon from Mogushan Vaults is being turned into a spirit beast in Shadowlands. Now I kind of want Mogu to be an Allied Race just to tame Cloud Serpents.

Anyways, Slash, the saddled Razzashi raptor (you can tame in MoP) and Blaithe (Aviana's ex-consort) have been by my side.

[zenyatta]

Gustiver aka Mazzranache. I'm actually so hard core about HIM SPECIFICALLY that on my alts, I won't just tame the pink ones in Southern Barrens, it needs to be him (yes, he/him/his, as the quest of the same name uses male pronouns).

When I was a fresh lvl 10 orc hunter, waaay back in BC I trekked my way out to Mulgore and waited for him. Then I rerolled Alliance a few months after... and made the journey on a draenei to go get him. He's muh boi, he's tanked things, he's helped me parse, he's always been my dude. No matter how many cool new pets come out, Cozzene and Mumtaz will forever have their 13 year old pink tallstrider at their side. Alts use whatever, but he's in their stables if not on their active Call Pet list.

[Razion]

Since I play Surv I tamed a tiny frog and shrunk it more with the glyph so I could see more in melee and target things better. What started out as a practical choice is now one I keep regardless of pet bonuses or abilities. I had just done the quests with Krag'wa before I got him, so I gave him a similar name. He's the best little frog and he has saved a lot of wipes. No one ever expects the tiny frog off-tank!