Each one seems to have it's uses when done right.... I'd try using abilities for these situations:

Speed Up/Down- Good for manipulating team speeds when you try to get all medals on a mission. You WILL need this if doing story stages for flower gems (maybe Nation Battles too).

Atk Up 1 Turn- The basic ability you should be using until you get something better. Also, when doing the whaleship (and having a lead team that smites everything), put this ability on everyone so you get more damage out of the Break sequence. You can't rely on crit (if it does allow you to) and it has no weaknesses).

Critical Up- Crit based teams love this.

Weakness Dmg Up- Good to use if you have nothing better (it's more useful than Atk Up 1 Turn in most cases). But on teams that have characters giving multiple weaknesses to allies (like Iberis and Burning Bush), this ability can further help you out.

Def Activation Up- Can be good for counter units (but there's still a better one). Very good for setups where you lower the enemy's hit rate and atk power, and for characters that can raise everyone's defense. hands down part of the best way to drag out raid boss battles and it's been used to reduce some bosses to 1 damage per hit if done right.

Recovery Boost- Good for those with pest nest skills, recovery while dealing damage, or if you have either chocolate cosmos. Healing even exceeds max HP as well so you get extra. so if you max it out, a 20k HP character can get to 25k.

Taunt- Best used for units that can dodge attacks or counter them. Combined with units lowering the enemy's atk and hit rate is another option. for best results, put it on a counter unit while lowering the enemy's atk and hit rate, while boosting the team's defense with someone. You should deal more counter damage while focusing all attacks on the counter unit.


it all depends on what you make of them, but all 8 should eventually be learned.