So, I found a guide for all the Collectibles in the game, and the Garden Gnome section included the text for each one along with coordinates, and they are FUNNY and full of references.
SPOILER - here are the names and texts, with what I think it is referencing added in by me.
Unpainted Garden Gnome This gnome is in desperate need of a paint job. On the plus side, his life is still a blank slate. - tabula rasa
Classic Garden Gnome The classic colors of the garden gnome. Quite the globe-trotter, he likes to take pictures of major tourist attractions. - I don’t know what this is referencing
Dark Side Gnome This gnome has let the hate flow through him. He tends to use his unhappy childhood and doomed love affairs as an excuse for his questionable life choices. - Sith, Star Wars
Devil Gnome His creator was very tenacious about becoming a rock legend. - JACK BLACK TENACIOUS D ROCK LEGEND
Evil Gnome He’s the ordinary evil: you wouldn’t pay too much attention to him in your garden, but best lock your door at night… - possibly Dr Evil’s son Scott Evil, just regular evil
Radiation Gnome The unfortunate victim of an accident involving radiation experiments. Don’t anger him. - THE HULK reference
Green Plumber Gnome Plumber by trade. He’s more on the timid, nervous side and leaves the spotlight to his older brother. - Luigi
Italian Plumber Gnome Officially a plumber by profession, he’s more prone to taking on new hobbies or sports - and excelling at whatever he does. - It’s-a me, Mario!
Light Side Gnome He seeks to bring balance to the gnomes, but unfortunately, he’s the last of his kind. - Luke Skywalker, Star Wars: The Last Jedi
Father Gnome A wise and father-like village elder. He’s much, much older than any of the other gnomes, but gets irritated when you point it out. - Father Time, I guess?
Gnome Princess She has the most fabulous of beards. - awwww
Purple Gnome The Gnome Formerly Known as Dwarf. Enjoys nothing like a rainy afternoon. - Prince (The Artist Formerly Known As Prince) and his album / song Purple Rain
Rainbow Gnome A gnome that loves peace and harmony. You won’t find him above a chimney top, though. - likes to stay clean
Red Gnome His first owners had overestimated how much Falu red paint they’d need to painting their countryside cottage. One night, they decided to paint the town red, then the gnome. - funny LOL
Bronze Gnome An alloy gnome made primarily from copper, tin and disappointment. He had his moment of glory for a while, but gradually disappeared when iron gnomes became more common. - Bronze Age of history ending, replaced by Iron Age
Silver Gnome Warning: hazardous to werewolves. - silver bullets kill werewolves
Swedish Gnome An old and free gnome, he enjoys cinnamon buns and long walks in the serene Swedish countryside. Surprisingly not a fan of fermented herring. - various Swedish references
Jultomten No one knows his real name or where he lives. The only thing that is established is that he runs an insanely effective package delivery system. - anyone know what this one is about? EDIT - Jultomten is Swedish Santa Claus! Awesome!
Yellow Gnome This ancient sea captain likes to tell young gnomes about his life sailing to sea. - Yellow Submarine meets Rime of the Ancient Mariner?
Hippie Gnome Still sporting the bushy beard of the early 1970s, this youthful gnome has yet to adopt a more modern hairstyle, such as the mullet. - hippies, I guess
Last-Gen Gnome It looks so realistic! - old console remastered games?