Ranger's Versatility

With a finely tuned affinity for the wild, you harness the magical power of Nature to enhance your skills and talents as a Ranger*. You gain the following enhancements to your Favored Enemy, Natural Explorer and Primeval Awareness class features depending on your ranger level:

Favored Enemy

• Whenever you complete a long rest, you can choose to replace one of your current favored enemies with a new type of creature you have encountered or interacted with (including its tracks or marks). Choose from the following creature types: aberrations, beasts, celestials, constructs, dragons, elementals, fey, fiends, giants, monstrosities, oozes, plants, or undead. Alternatively, you can select up to two races of humanoid (such as gnolls and orcs). This enhancement does not grant you an additional language linked to the new favored enemy.
• By 6th level,  your knowledge of your favored enemy now allows you to find weak points in its defenses. The first time each turn you hit a favored enemy with a weapon attack, you can re-roll the weapon’s damage dice and use either total. From 14th level, this extends to all successful weapon attacks you make during each round of combat against a favored enemy.

Natural Explorer

• You react swiftly and decisively when threatened, and have advantage on all initiative rolls. 
• From 10th level, after completing a long rest in a terrain other than one of your favored terrains, you can adapt to the new terrain and treat it as though it were one of your favored terrains. 24 hours after you leave the new terrain type, these benefits cease, and you must complete another long rest once you re-enter that terrain type in order to gain these benefits again.

Primeval Awareness

• Your Primeval Awareness feature also grants you an innate ability to communicate with beasts, and they recognize you as a kindred spirit. As an action, through sounds and gestures, you can communicate simple ideas to a beast and can read its basic mood and intent. You learn its emotional state, whether it is affected by magic of any sort, its short-term needs (such as food or safety), and actions you can take (if any) to persuade it to not attack.

*Note: The elements herein are designed as  a 'patch' of sorts for the PHB core ranger class, offering some flexibility and enhancements from the Unearthed Arcana Revised Ranger, with a keen eye on maintaining balance. By requiring a minimum of 3 ranger levels, it avoids temptation to 'dip' into the class to cherry pick these enhancements. This feat could be offered to players as a normal feat, in lieu of ASI, or if a DM preferred, it could be automatically granted to boost playability of the class.