Disguising the Character
Change the appearance of your character with disguise. Possibly all you need to add is something as simple as sunglasses. Or maybe sometimes you need something more extreme, such as sunglasses with a fake nose and a mustache.
Take two of your character designs and create an analogy between them. Take different characters and make something about them similar. For example, how could you make a weight lifter and ballerina seem more similar? Could you add a tutu to the weight lifter? Could you add something else? As you see what the results are, continue with differing and additional characters.
Creating a Hybrid
Create a hybrid by taking two of your characters and imagining that they produce offspring. What would happen if one of the characters were a robot and the other were a plant? No combination is too outrageous.
Evolving the Character
Evolution is a very subtle process, with change being gradual and sometimes hardly visible. Evolving a character can be one of the most fun and rewarding ways of creating new and exciting characters. Simply pick something about your character design and modify it slightly. Take this changed character and then alter the changed element slightly. Continue with this type of progression as long as you like.
Superimposing is similar to combining characters or objects, except that instead of mixing two separate objects together, you are superimposing one over the other. This can be done at more than one level. Again, you are encouraged to try things that you normally would not consider doing.
Changing the Scale
Take a part of your idea and change the scale. Change the scale of your whole character if it will work. To effectively change the scale of an object, you must include something within the image or on the character to give a visual clue as to the scale.
Making a character a giant does not work unless something around the character gives visual clues to the imposing size. The reverse is also true if you are making a diminutive character.
Substitute a portion or prop of your character with something different. Perhaps even substitute something really different. Make that sword a paintbrush or vice versa.
Distortion is very self-explanatory. Shear, twist, fold, spindle, and mutilate your character, portions of your character, the original idea, the costume, anything. Nothing is sacred or beyond your ability to distort.