This achievement is for the abilities found in mind, muscle, and power. This will also include the God Key abilities that are unlocked late into the story. Many people are stuck on the "what level would I need to get to in order to unlock all of the abilities" argument. While it is helpful to have a general idea (level 80+) that number is quite flexible.
By turning in missions on other people's worlds you will end up getting ability points that your solo grind does not account for. It's for this reason that I ended up unlocking this quite a bit earlier than initially planned. Quick joining random people's worlds also gives you an opportunity to kill low leveled enemies for weapon ranks.
Lastly, at the very end of the game is a Treasure Hunt side quest that will award you with one ability point per treasure found. This is a great way to grab some easy points in the post-game portion.