Blue
Ravenous Bugblatter Beast of Traal
The easiest way to describe them is to describe their purpose.
The Ranger is a guide, hunter, tracker, and/or wilderness liaison. The ranger is a job.
WOAH. That's a massive narrowing of the ranger, one that does not match with existing crunch, existing fluff, nor with the fact that they get nature related spells.
Sorry, I am not accepting that limiting of scope. First, we already have a wider scope in play, we can't "put it back into the box". Second, 5e is designed with wide base classes and more specialized subclasses. Narrowing a base class like that is against the design philosophy.
The Wilderness Warrior, the Scout, and the Green/Ancients Knight on the other hand as primarily about their base skills. The Wilderness Warrior is a Fighter. The Scout is a Rogue. The green/ancients knight is a paladin They fight like their classes. They just get along with nature better. One might ride a giant lion as a mount. Another might be an expert at using primitive weapons and handling animals. Another might be good at ambushing. But they are their base class primarily.
Got it. Wilderness Warrior is a fighter with the outlander background - fighter with nature skills. Scout is the rogue subclass. Green/Ancients Knight is the Oath of Ancients Paladin.
The Warden and the Seeker are two halves of the same coin. They are warriors imbued with natural mystical powers. They enhance their weapons and armor with natural primal power for some purpose. The Seeker focuses on enchanting their ranged weapons and ammunition. The Warden focuses on enchanting themselves and everthing they touch. In 5, they easily could be two subclasses of the same primal warrior class.
There's no need to toolbox 5e. There's plenty to missing stuff from the past for D&D 5e to make.
Seeker seems to fall under the existing Ranger. Warden doesn't seem to be described in any way connected to nature except describing a pwoer source so I'm not sure where to go from there.