Shippo Shippo no Mi / Tail Tail Fruit
This Paramecia-type devil fruit allows the user to grow a tail for themself at will, making them a Tail Human. With increased proficiency in this fruit, the user can increase the size of the tail, either in length or width, or even create more tails.
The character I gave this fruit to primarily combines it with Rokushiki abilities to maximize the effectiveness of her otherwise underwhelming fruit. She uses Tekkai to harden the tips of her tails, making them hard and sharp, or using the hardened tails as shields. Additionally, she also uses Rankyaku with her tails, and Kami-e to make them adopt unusual shapes
Fuwa Fuwa no Mi / Fluffy Fluffy Fruit
This Paramecia-type fruit allows the user to create and transform into cotton-like fluff, making them a Fluffy Human. The fluff could be considered to be made of the same substance as Doflamigo's strings. Similar to Katakuri's fruit, the user is technically always in this state but occasionally may make this more obvious during specific techniques. Because of their light body, the user becomes incredibly fast and has a much easier time using Geppo. While visibly transformed into fluff, the user becomes even lighter while remaining just as physically strong. The more the fluff that the user is comprised of spreads out, the lighter they become, and they can essentially fly while fully spread out but cannot attack. The awakening of this devil fruit, like most fruits, lets the user turn their surroundings into the substance they can control, that being fluff in this case.
The character I gave this devil fruit primarily exploits her light body to use Soru and Kamisori with incredible effectiveness. She also creates fluffy creatures that are capable of acting with some level of independence from her and flying. Additionally, she creates fluff bombs by making a ball of compressed fluff and then releasing it
Garasu Garasu no Mi / Glass Glass Fruit
This Logia-type devil fruit allows the user to become glass, making the user a Glass Human. The glass the user transforms into is both rigid and amorphous, like normal glass but to a much greater extent. Essentially, the user acts like a viscous liquid but shatters when struck. When the user produces a lens from the glass that they transform into, its ability to focus light is increased, and can be used to produce powerful lasers from the sunlight around them, or even moonlight with enough time to charge.
San San no Mi + Enki Enki no Mi / Acid Acid Fruit + Base Base Fruit
These two would either be Logia or Paramecia type. When eaten, they would give the user the ability to produce an acidic or basic liquid respectively, making them either an Acidic Human or Basic Human. The user of either fruit can change the acidity or basicness of the liquid as long as it is 6 and below or 8 and above respectively. I could see two characters having this one and using it in tandem to be immune to each other's abilities.