Thematically, some of them have abilities that play well with other cats, like lifegain and +1/+1 counters, while other legendary cats are off doing their own thing
Whats great about both Holo and Reverse Holo treatments is that you can find them applied to just about any card so you can even find Common cards with holographic treatments
In the last callback to zombie tokens, the most recent core set also gets a brand new goblin token, this alley-dweller courtesy of Filip Burburan

Julius Jumblemorph Ego Erasure Feisty Spikeling Firdoch Core Fire-Belly Changeling Flock Impostor Formless Genesis Game-Trail Changeling Gangly Stompling Ghostly Changeling Gladewalker Ritualist Graveshifter Guardian Gladewalker Impostor of the Sixth Pride Irregular Cohort Littjara Littjara Glade-Warden Littjara Kinseekers Masked Vandal Maskwood Nexus Mirror Entity Mischievous Sneakling Mistform Ultimus Mistwalker Moonglove Changeling Moritte of the Frost Morophon, the Boundless Mothdust Changeling Mutable Explorer Nameless Inversion Omni-Changeling Omo, Queen of Vesuva Overlord of the Hauntwoods Personify Prideful Feastling Realmwalker Rooftop Percher Runed Stalactite Shapesharer Shields of Velis Vel Sizzling Changeling Skeletal Changeling Springleaf Parade Stalactite Dagger Taurean Mauler Three Tree Mascot Turtleshell Changeling Universal Automaton Unsettled Mariner Valiant Changeling

I considered putting Sorry in the main body of the article, but it's basically, well, got a similar concept with a lot of the other Unglued blue cards