Curate, connect, and discover
So we all know Percy is powerful as shit, there's no doubt in that. But I think I may have thought of a few more (theoretical) applications of his abilities. These ones aren't insanely broken (except one I had to give up on cause I couldn't find a way to make it work), but they're still pretty good.
Percy can control liquids with water in them. We learned this in Tartarus when he drowned Akhlys in her own poison. So in theory, he can bloodbend, right? But this is actually incredibly good in a defensive sense. Since he can control blood, including his own, he can use his powers to (theoretically) negate blood loss and keep his blood inside his own body, keeping him in the fight for much longer. Hell, this circumvents internal bleeding when you think about it.
Speaking of bloodbending, in the same Avatar episode that that idea is introduced to us, we learn that water can be taken from plants, as well as animals (although that is harder as far as I know). Okay, so Percy can take water out of plants, cool. But what about the atmosphere? Sure, the amount of water in the atmosphere varies wildly depending on location, season, etc. But the point still stands. In theory, Percy can pull water out of his surroundings and use it to heal himself, further improving his durability, and giving him an overall stat boost, as he just performs better in water in general.
Imagine fighting Percy, thinking you've got him beat, when all of a sudden he pulls out a Dragon Ball-esque transformation and surrounds himself in a thin coat of the water from not just the atmosphere, but his sweat, your blood, hell, YOUR sweat, and any other possible sources of water nearby. Bloody terrifying. Especially when you consider Percy killing -> Percy receiving access to blood -> Percy getting stronger -> Percy killing more, basically creating an infinite cycle of steadily increasing strength (providing his enemy has blood, naturally).
So yeah. Percy, using his abilities correctly, isn't just insanely strong, but pretty damn durable too. I did have another idea about him controlling brain fluids/breathing in oxygen through water to circumvent brain death, but that kinda fell through because brain fluids aren't really related to brain death and you need lungs to, you know, breath, which would circumvent the decapitation scenario I was thinking of, and Percy can't breathe through osmosis (as far as we know). So that idea is a bust.
...Unless Jason could manipulate oxygen into his bloodstream, using his abilities to circumvent brain death instead...