Examples of good HP boost targets
Note: you can click on the images below to see them bigger.
Example 1
Momo has enormous defence, is stun protection so you want it to be hard to kill, deals 6k piercing damage any time it attacks and it can even heal itself when it switches between protector and stun counter so regains the extra HP. It’s a very strong mythic and a clear choice as one of the best for HP boost.
Example 2
Plumesilisk is a protector so will get in the way of more attacks with the boost. Also, the HP boost is passed onto the protector babies so they will become proportionately even more tanky. The damage output here is lacking, but it doesn’t matter because you can use it primarily for protection and support.
Example 3
Gremoris has high defence and on its first turn can begin putting the enemy team to sleep so making it harder to kill before that is useful. Dreamcrush deals well over 6k piercing damage and Gremoris wants to stay alive a long time to invoke and charge bloodbath (or invoke others too) so HP boost helps it stick around. The SS damage is poor, but you can just have that turned off.
Example 4
Elemphox (shadow) needs to be used with a holy monster then has very high defence and deals enough damage with flaming blaze and stone missile. The control with frozen punch and thundering strike is very powerful, regardless of the damage dealt. Hold ground and poison immunity make it hard to take out without piercing and a great target for healing.
Example 5
Bastia has enormous defence and doesn’t care about damage because it’s full support. Healing itself is stronger when it has boosted HP but it’s especially good to be healing other tanky HP boosted monsters on your team. Goddess’ protection on a fully HP boosted team is very hard to get through.
Example 6
Mantiferno has low defence and can easily be killed before it gets a turn so it’s definitely not the best choice. However, the accelerate on your team is guaranteed and powerful plus when it does get turns it can then rapidly do 6k+ damage piercing attacks (man eater is actually 68TU because of the acceleration and +9 bonus, raw mark is 33TU into 88TU raw cornered snipe then 88TU bloodfury). This example is to show that, while not ideal, there are some monsters like this which are strong and can do enough damage they may be worth HP boosting after the best ones and you should look for stuff like this rather than weaker monsters with high defence.