The three classes of devil fruit in One Piece are logia, zodiac, and paramecia. It's often said that logia type powers are the strongest and paramecia are the weakest. However, I noticed that there are weak logia fruit powers like one from the swamp-swamp fruit, and strong paramecia powers like one from the tremor-tremor fruit. This a list of the strongest paramecia fruit powers.
Gum-Gum Fruit - Here it is. The fruit that started it all. I'm sure a lot of you are wondering why I have Luffy's fruit ranked so low (though this being the internet, I'm sure a decent few of you are hurling horrible insults at your computer). I believe that most of the power that we have seen so far lies in its user, Luffy's, unpredicatability. I originally had no intention of putting it on the list at all. However, I remembered that it is capable of a great many things. It makes Luffy automatically bullet proof, allows him to inflate himself to gigantic proportions, and he can even blood dope himself using it. Also, there's the whole thing where if you stretch a rubber band and then release it, it well sling back with high speed and inflict sharp pain on whosoever was unfortunate enough to be in its way.
9. Stone-Stone Fruit - This fruit allows the user to assimilate with any kind of stone. After assimilation, they can then control it. Through this ability, Pica has made multiple golems and has even controlled an entire castle. How can someone win a fight against an entire self-repairing building?
8. Hobby-Hobby Fruit - There is no way I can leave this one of this list. It helped enslave an entire nation for 10 years. It allows the user to turn whoever they touch into a toy. On top of this, it makes everyone forget about the person. The user, currently Sugar, is also capable of controlling these toys. The downside is that it turns the user into a child.
7. Art-Art Fruit - This fruit turns people into art. To be more specific, it turns them into extremely ugly sculptures. It can also do this to things. Of course, there is no such thing as a fighting sculpture, so the fruit removes all combat effectiveness. If you ask me, rendering all of your opponents unable to oppose you is just as effective as killing them.
6. Venom-Venom Fruit - Luffy almost never loses a fight. That's just a fact. By the end of the arc the main villain is always pummeled to a pulp or sent flying team rocket style. This is true with few exceptions. One of them being the one who ate this fruit. He beat Luffy down so bad that he almost died. Actually, it was so bad that the only cure for all the poison had an extremely high chance of killing him as well.
5. Paw-Paw Fruit - This is the power that separated the Straw Hat Pirates for two years. It is capable of pushing anything at ridiculous speeds including the air. Bartholomew Kuma often uses this power to push the air causing it to become powerful force. This power can be used to "push" pain and fatigue out of one person and into another. He also sent every last member of the Straw Hat Pirates flying for approximately 72 hours non-stop to 9 different locations of his choice.
4. Love-Love Fruit - Okay, the name is very unintimidating but the power is incredible. It allows the user (currently Boa Hancock) to turn someone to stone from both a distance and up close. Afterwards, the statues can be broken thus killing the person. Also, those turned into stone kept that way until the user decides to free them.
3. Op-Op Fruit - This is Trafalgar Law's fruit. With it, he can put an area under his control. In his "operating room", he can do whatever he wants to anyone's body. He can switch peoples' minds, remove their hearts, (without them dying) and do all sorts of other horrific things that would make normal people die from shock.
2. Tremor-Tremor Fruit - This was eaten by Whitebeard and with it he basically punched people with earthquakes (no idea how you can hold an earthquake in your hand). The attacks were powerful enough to nearly kill Akainu despite the invulnerability logia users have. This fruit makes the user so powerful that I believe it completely outclasses most of the logia fruits (unless there's some secret water-water fruit not yet revealed).
1. String-String Fruit - This fruit gave Doflamingo his powers. With it he is able to use clouds as transportation, control people like puppets, slice and or penetrate through people or objects, and even make clones of himself capable of using his powers made out of string. Also, he completely caged the entire island of Dressrosa with the strings he created using this fruit. They are even capable of cutting denden mushi signals. On top of this, we have yet to see its full potential.
Log Horizon - It seems like Sword Art Online at first sight but once you watch it, you realize that it is quite different. Of course, they all get teleported into their favorite MMO-type game. However, absolutely no one has any idea of what's going on and there are a lot more than just sword skills being used. Shiroe, (someone who made it onto my smart shounen protagonist post) is the main character. He finds a few friends along the way and decides to create order in the game world with them until they figure out how to get back to the real world. Oh, and to make it even better, season 2 just started up not too long ago.
Magical Warfare - This is actually one of, if not the best magic anime I have seen. Takeshi Nanase is at school during break (poor guy) and he finds a strange girl unconscious on the ground. He picks her up and carries her into the infirmary as any gentleman would. Still, she improperly assumes he has malicious intentions and shoots him. The bullet does not kill him but transforms him into a magician, for which she apologizes. Now, he must figure out just what is going on and what to do with his new powers
Akame ga Kill - A very untypical story of a small town boy striking out and going into the big city. For one, there are gigantic monsters he has to fight to get there. Secondly, he ends up on a team of assassins rebelling against the corrupt capital. This anime has a lot of unique weaponry and great fight scenes; watching this is definitely a must for any action lovers.
Black Bullet - Black Bullet is set in a near future where humanity has been driven into a corner by giant, virus carrying monsters called gastrea. As its counter attack, humanity sets up a special civil security force dedicated to eliminating gastrea. The story follows civil security officer Rentaro and his partner Enju as they take on assignments as well as deadly adversaries.
Soul Eater - The world is one where the Grim Reaper has created a school to teach kids how to collect souls from heinous criminals and witches (sounds crazy huh?). The story follows a girl named Maka and her partner (which means literally human weapon in this world) Soul Eater as they complete various missions, make allies, and get caught up in dire situations.
Yoshino Takigawa (Blast of Tempest/Zetsuen no Tempest) 
Lelouch vi Britannia (Code Geass: Lelouch of the Rebellion) 
Shiba Tatsuya (The Irregular at Magic High School/Mahouka Koukou no Rettousei)
Shiroe (Log Horizon) 
