Trump talks about his little schlong during a debate.
Building a wall is the central most important part of his campaign's beginnings.
Dismisses POW Senator and one time presidential nominee of your part as a loser who got caught.
Attack parents of soldier because they disagree with you and comparing his loss and sacrifice to theirs.
There's 30-40 more, these just came to mind.
Comrade Manafort
Trump admitting he could shoot somebody on Fifth Ave. and not lose any supporters.
Encouraging violence at his rallies (I wanted to punch that guy, offering to pay legal bills for an assault charge).
Going Moe from Three Stooges after criticism in the wake of the DNC - I just wanted to... Why I oughta... I just wanted to... Why I oughta... hit that guy, so hard, it would make his head spin.
At a security briefing asking three times why he couldn't use nukes.
In a post Cold-War, Dr. Strangelove landscape of MAD, he is quoted that he wants to be "unpredictable" with nukes.
He knows more about ISIS than the generals and has a plan to defeat them only it is a secret so ISIS doesn't know - the secret plan is later revealed to maybe involve asking generals what to do, and he'll recognize a good plan if he sees it.
He would solve all crime in the first week because he talked to some "strong looking guy" who may or may not have been in the Chicago Police that nobody seems to know about.
Dwayne Wade's cousin is shot and his first instinct is to say - Told ya so.
Makes an aggressive illegal immigrant policy a cornerstone of his campaign strategy, than it comes to light that he employed undocumented Polish workers (who he then stiffed their pay). His wife Melania may have illegally worked and stayed in the country with the wrong kind of visa.
Complains about pay for play, than his "charitable foundation/slush fund" is caught bribing a Florida woman to not bring fraud charges against Trump U. In a deposition, he can't remember that he claimed he had the world's greatest memory.
Brags about exploiting BK loopholes because that is what the US system permits and successful businessmen do, leaves thousands of small business workers in Jersey casinos holding the bag, than talks about how he stands for the "little guy".
Repeatedly rails on Obama and Clinton for causing the Iraq War as if they started it (and not Bush) and talks about how he wasn't for it, though their is irrefutable evidence of a Stern interview in which he was, than when repeatedly corrected, keeps perpetuating the lie, seemingly on the basis if you tell a lie enough it becomes the truth.
His surrogate "Crazy" Katy Pierson claims Obama and Clinton policies caused the death of the Khan's son - a half decade before Obama was elected.
They trot out a Russian born campaign adviser with a thick accent named BORIS unironically claiming there is no connection between Russia and the campaign.
Trump seriously asks Russia to spy on the Clinton campaign to influence the election, than when the press turns on him, berates the "dumb press" for not telepathically realizing he was "being sarcastic".
Countless politicians and security agents extending to high levels of government ON BOTH SIDES OF THE AISLE warning that Trump is not only not a serious or credible candidate, but extremely dangerous and temperamentally unfit for excutive office.
Chronic, habitual pattern of second grade insults and bullying tactics earlier in the Republican debate process.
The whole recent Mexican escapade/fiasco where he claimed they had a great meeting yet just a few hours later the Mexican President ended up in a Twitter war with him, not to mention the bizarre fugue state in which fire and brimstone, deport everybody Donald morphs into a kinder, gentler, softer "Amnesty" Don, than is back to wanting to deport more than 10 million people ASAP - ALL WITHIN A POLICY WHIPLASH-INDUCING 24 HOURS!!!
For a time sabotaged his own party by withholding support for Ryan and McCain due to personal grudges (making himself look petty, juvenile and vindictive in the process).
Claims the fix is in on the election before it is even over, while having no lucid, coherent or intelligible ground game prep of his own, and solicits extra-legal private election day voting booth security/militia watchdogs (i.e. - roving bands of Boss Tweed, Pendergast Machine-like goon squads) to ratchet up the intimidation factor, when some states such as Florida permit concealed weapons - what could go wrong?
There are probably actually hundreds if not thousands of such instances.