Fully Loaded Achievement
Invest in all Special Abilities for all Companions.This achievement requires you to buy all three abilities for Star Lord, buy the remaining two abilities for each of the other four Guardians, and then unlock the final ability for all five Guardians. The final ability for all five Guardians is unlocked automatically through story progression; the rest require ability points. As a result, you will need 26 ability points to unlock all Special Abilities and this achievement.
Despite seeming like a large amount of points, especially early in the game, this achievement is actually essentially progression related. There are no optional ways to gain XP towards ability points. All combat in the game is mandatory. On top of that, XP from combat is a set amount regardless of how many enemies you fight and kill. While your Momentum bonus can give you more XP, it's not often a significant amount, plus it's pretty difficult to finish a fight without at least a moderate Momentum bonus.
As a result, you will unavoidably get enough ability points to unlock all Abilities before you complete the game. I unlocked them all by Chapter 13, and there are a ton of fights in Chapter 14.