I am LVL 52 in horizon, i have all cauldrons, tallnecks, side quests, errands, tutorials, metal flowers, bunok figures, corrupted zones, bandit camps, and all blazing sun's in all hunting trails but I still need 15 skill points. Currently on the loaming shadow, where I must rest before the battle. Am I missing something? I should have them all before I finish the game, right?
Since you are level 52, I can safely assume you have the Frozen Wilds Expansion.
Let's break down which skill points you can obtain. Reddit has a very nice breakdown. With the Frozen Wilds Expansion, there are a total of 101 skill points available
- 17 skill points can be obtained by story quests
- 4 skill points can be obtained by side quests
- 20 skill points can be obtained by activities
- 60 skill points can be obtained by levels
Unclaimed Skill Points
You are level 52, meaning you have a total of 8 more skill points you can acquire by levels. This leaves only 7 unaccounted for.
You didn't list out finding all Vantage Points. According to reddit, you get 1 skill point per set. It's been a while since I've played Horizon Zero Dawn, but if this is accurate, you can get 3 skill points from this. This leaves 3 unaccounted for.
If you have covered all the basis from above and you are still short skill points, you can always grind the final mission until you have unlocked all the skills.