What I admit I do like about early Pokemon is how rarely they went for the easy ideas first. They had to create 150 monster designs in one game, and I’m sure it could’ve been so easy to phone it in with some generic RPG-ass monster designs, but it took six generations for them to make a Pokemon based on a tree, seven generations for them to make a wolf. The grass type representation in gen 1 is palms, rafflesia flowers, pitcher plants, and cordyceps fungus
The first games introduced the concept of reanimating fossils, and the first fossils you can resurrect are horseshoe crabs, ammonites, and one (1) pteranodon. It took four generations before you could reanimate a dinosaur, and it took two more generations before you could reanimate a Tyrannosaurus rex
Gen 1 did have some generic RPG-ass monster designs (slime, snake, bat, Big Guy Made Of Rocks) but a lot of it is weird biology, visual puns, and references to Japanese folklore and pop culture. It was so much more important to make a Pokemon referencing the phrase “a duck comes bearing green onions” than a wolf, and I think that’s a load bearing pillar to the series’ ethos towards monster design