Thanks for posting this early! As per usual, initial thoughts:
Magic: First, I am very definitely happy that this is spell-less and only grants archetype spells. The only suggestion I could possibly make here is to make one of the knacks or other traits the ability to basically get the Magic Initiate feat, where you could get two druid cantrips and one druid or ranger spell. As an option, it opens up the door for people who like more magical rangers without making them into half-casters.
Familiar Terrain: The main change I would make would be to change the phrase "After 14 consecutive days of traveling" to "After 10 consecutive days of traveling or living in." Ten days just in case there are people out there who actually use FR's tendays (also, rangers don't need no stinking calendar), and living in because camping out in the wilderness or living in a wilderness fort is different than traveling through the wilderness en route to somewhere else, but both give you the option of learning the surrounding area well.
The other change I would make is, in the Druid packet, you had "Eldritch Survivor" as a knack. You should include Magical Lands as one of the options here--doubly so now that Tasha's includes Supernatural Regions.
Now, the following is an issue with the wording of the PH ranger: "you remain alert to danger." For the life of me, I can't remember if there are any actual rules for
not being alert to danger.
Studied Adversaries: "Two humanoid heritages." Does this mean that this would include people of mixed heritage as well? You might want to note that.
A thought: While there aren't a lot of monster tags that aren't humanoid heritages, there are a few: shapechanger and titan, off the top of my head. Perhaps these should be options for rangers as well. I can imagine a doppelganger hunter who doesn't care about other monstrosities.
Also, personal plea: I have no idea if you're going to also put out a monster book at any point (hey, Pathfinder has multiple books, and they started out as a 3.75 edition), but perhaps Giant and Humanoid could be blended together, with giants having a [giant] tag. Because what's the difference, really, between a Large humanoid and a Large giant?
Maneuvers: Hmm, new maneuver. Are you actually planning on putting all the maneuvers in their own chapter now? Because fighters could definitely benefit from Soldiering.
Stride and Seek: Since
Sniper has definition connotations of distance attacks, perhaps rename Sniper's Target to just Target, or Marked Quarry, or something like that.
Trained Accuracy: This seems awfully complicated. I'd say that for every 1 exertion you spend, you get either +1 to hit or +1d6 to damage, to a maximum of spending 6 exertion for +3/+3d6. If you're worried that's too much damage, just make it +1d4.
(Semi-related: do you have any plans on bringing back masterwork weapons, and if so, how?)
This makes me wonder why rogues get a flat bonus to damage and not something like this.
Accuracy Reserve seems far too powerful.
Answering Silence: Because you're
terribly mysterious. I am amused, even if it's not particularly logical.
Game Hunting: First, you might want to define "game animals." Any beasts? Beasts under a certain CR? Because "game animals" has also included large animals like elephants, which are high CR. Also, logically in D&D-land, if you're allowing for high CR beasts, you should include monstrosities with an Int of 3 or lower, like griffons and owlbears. (Like Eberron did.)
(Second personal plea: if you actual create an MM, stick nonmagical monstrosities like this in the beast section. Give 'em a [magical hybrid] tag that means druids can't shapeshift into 'em, if you like, but seriously, things like that should just be treated as normal D&D beasts)
Versatile Exploration: Approve. I'm tempted to put Rogue on that list as well.
Beast Friend: Approve. Perhaps have an ability that allows you to spend additional exertion for higher CRs (perhaps requiring you to take this knack multiple times).
Grub Hunter: Ewwww!

Slimy yet satisfying.
Poisons and Antidotes: You should be able to use this to milk a snake, grab the venom sacs off a wyvern, giant scorpion or other living/just slain creature. In fact, this ability should be rephrased as "you gain proficiency in the Poisoner's Kit, if you didn't already have it,
and you gain the ability to make poisons out of plants and animals."
Soldiering: I feel like you should divide this into Soldiery and Calvary/Mounted Combat.