Here is a list of interesting word types and phrases that may spark ideas for any wordplay puzzles you might want to design.

A form of reduplication where the vowel in each duplicated word is changed. In English, the vowel order is almost always I-A-O for tripled words (as in "ding dang dong," "bish bash bosh" or "Fing Fang Foom"). With any pair of words, the first vowel is almost always I, while the second is either A or O (as in "crisscross" or "bric-a-brac"). Reordering the vowels (as in "knack-knick") will make a reduplication sound bizarre to English speakers' ears. Compare with rhyming reduplicationshm-reduplication.

A word formed using individual letters or sounds from a longer description. Examples: SCUBA for Self Contained Underwater Breathing Apparatus, or RADAR for RAdio Detection And Ranging. Compare with initialism. 

A word that reads the same when turned upside down. Example: SWIMS. Ambigrams can created by clever use of calligraphic curves.

A name created by spelling another name backwards. Examples: Harpo Productions (Oprah Winfrey's media company), the Castlevania villain Alucard (Dracula spelled backwards). See also semordnilap.

A word that is the opposite of another word. Examples: BIG is an antonym of SMALL. NEAR is an antonym of FAR.

A word that describes itself. Also autological word. Examples: POLYSYLLABIC, WORD, PRONOUNCEABLE.

An acronym assigned to a word long after it has been coined, usually to (incorrectly) explain its origin, or for humourous purposes. Examples: FUCK = Force Unlawful Carnal Knowledge, TAG = Touch And Go.

A word that can be capitalized to change its meaning (and sometimes pronunciation). Examples: China and china, Polish and polish.

A form of vernacular code or euphemism from the East end of London in the 19th century, where a target word is rhymed with a pair of words, and the rhymed word is potentially dropped from the phrase, leaving the first (non-rhyming) word in the pair to indicate the target word. Examples: "Let's have a butcher's" (butcher's hook = look), "I'll take the apples and pears" (stairs).

A word that is its own opposite. Also auto-antonym. Examples: EXECUTE can mean to start something (as a plan), or to end it (as a person). LEFT can mean departed, or remaining.

The use of a negative word in place of a neutral one. Examples: "loony bin" for "mental health facility." Compare with: euphemism.

(Also "oronym.") A mispronounced or misspelled word or phrase based on mishearing or misunderstanding. Examples: "eggcorn" for "acorn," "for all intensive purposes" instead of "for all intents and purposes," "should of" instead of "should have." Compare with mondegreenmalapropism.

The use of a more palatable word in place of a harsh, blunt, taboo, or obscene one. Examples: "sensitivity" for "pain," "passed away" for "died." Compare with: dysphemism.

When an (often) hyphenated word contains the same, repeated word. Examples: bye-bye, pee-pee, choo-choo. Compare with rhyming reduplicationablaut reduplicationshm-reduplication.

A word that has entirely fallen out of general use, but remains viable as part of an idiom. Examples: to and fro, in high dudgeon.

A word that has one spelling, but different pronunciations and meanings. Examples: BOW (of a ship) and BOW (tie), DOES (acts) and DOES (female deer).

A word that is spelled the same as another word, but has a different meaning. Examples: DOWN (bird feathers/direction), PRIDE (confidence/a group of lions). See also: homonym.

A word that is pronounced the same as another word, but has a different meaning (regardless of spelling). Examples: HEIR and AIR, TWO and TOO. See also: homograph.

A word comprised of the initials of a longer description where each letter is pronounced individually. Examples: FBI, HTML. Compare with acronym.

A phrase where a certain letter or set of letters is deliberately omitted. Example: The phrase "John took two plums, just as Mom told him not to" does not contain the letter "e." Compare with univocalic.

The (often humourous) combination of two common metaphors or figures of speech. Examples: "It's not rocket surgery," "Til the cows freeze over." Compare with: malapropism.

The use of an incorrect word, often to humourous effect. Named for the character Mrs. Malaprop in a 1775 play. Examples: "A rolling stone gathers no moths" (moss), "She's as headstrong as an allegory on the banks of the Nile" (alligator). Compare with: malaphor.

A word used in a phrase where something represents a larger concept or idea to which it is closely related. Examples: "The pen is mightier than the sword" (the written word is mightier than violence or war), "Give me a hand" (give me some assistance). Similar but distinct from synecdoche.

A misheard word or phrase, often in a song lyric (and often to humourous effect). Examples: "'Scuse me, while I kiss this guy" (kiss the sky), "Hold me closer, Tony Danza" (tiny dancer).

A recently-coined word or phrase, or a new usage of an established word or phrase.

A word that imitates a sound. Examples: BANG, CRASH, VROOM.

A word or phrase that is spelled the same way forwards as backwards. Examples: RACECAR, DO GEESE SEE GOD? See also: semordnilap.

A word that appears to mean one thing, but actually means something quite different (or even the opposite). Examples: ENERVATED means weakened, not energized. INFLAMMABLE means flammable, not incombustible.

Latin for plural only, a plurale tantum is a noun with no singular form. Examples: CATTLE, SCISSORS, PANTS, TROUSERS. Compare with singulare tantum.

A combination of phonemes from two different words that create a new word. Examples: smoke + fog = SMOG, breakfast + lunch = BRUNCH, spoon + fork = SPORK. The word portmanteau is, itself, a portmanteau (porte + manteau = coat rack) which makes it an autonym.

A form of reduplication where the words sound similar. Examples: boogie-woogie, super-duper. Compare with ablaut reduplicationshm-reduplication.

A word that spells a different word when read backwards. ("Semordnilap" is "palindromes" spelled backwards.) Examples: BAG<->GAB, RAT<->TAR. See also: palindrome.

Latin for singular only, a singulare tantum is a noun with no plural form. Examples: ADVICE, CLOTHING, WEATHER. Compare with plurale tantum.

neologism derived from the fact that the Inuit have many words for snow, a snowclone is a phrasal template that journalists overuse to the point of cliché. Examples: X is the new Y, X-gate (from "Watergate," the -gate suffix being applied to any and every scandal).

A word or phrase for part of something that is used to represent the whole thing. Examples: "wheels" referring to an entire vehicle, or "mouths to feed" referring to hungry people.

A slip of the tongue where letters from two words in a phrase are swapped, often to humourous effect. Named for the Oxford don and minister William Archibald Spooner, who frequently made the error. Examples: "The Lord is a shoving leopard" (loving shepherd), "know your blows" (blow your nose).

A word with the same meaning as another word, but with a different spelling. Example: HUGE and GIGANTIC.

Words which, often due to a certain prefix or suffix, appear as though they should have an antonym, but they don't. Examples: "disdain" vs "dain," "bashful" vs "bashless," "deceitful" vs "deceitless."

A phrase deliberately written to use only one vowel. Example: A poem by C.C. Bombaugh begins "No monk too good to rob, or cog or plot. / No fool so gross to bolt Scotch collops hot." See also lipogram.

A word game invented by Lewis Carroll (of Alice's Adventures in Wonderland fame) where the goal is to move from one word to another by a series of one-letter transformations, where each transformation must produce a valid word. Example: SAIL to RUIN can be accomplished like so: SAIL->RAIL->RAIN->RUIN.