The angles worth testing come from three places, and a brainstorm is not one of them. Your own customer reviews, your competitors' live ads, and the gap between what your category talks about and what you do not.
Start with your own reviews
Your customers have already told you why they bought, in their own words, at length, for free.
Read them for the recurring phrase rather than the praise. People will say the same oddly specific thing over and over, and that sentence is usually a better headline than anything written in a brand voice.
Look especially for the objection that keeps appearing. The thing people say they were worried about before they bought is the thing stopping everyone who did not buy. In one account we looked at, the fear of being sold something you did not come in for was the fourth most common theme in the brand's own reviews, and it appeared in none of their ads.
Count your competitors' ads, do not remember them
Everyone thinks they know what their competitors run. Almost nobody has counted.
Open the Meta Ad Library, find the competitor by page ID rather than by name, and go through the live ads one at a time. Keyword search is unreliable: searching one brand name returned 974 results, not one of which was the brand.
You are looking for two things. Which concept repeats most, because that repetition is their own spend voting for what works. And which arguments nobody in the category is making at all.
A concept running for months is a concept that is paying for itself. That is the closest thing to free performance data you will ever get.
The gap is the opportunity
Put the two lists side by side. What your customers keep saying, and what your category keeps advertising.
The angles worth testing first are the ones your customers care about that nobody in your category is running. You have evidence of demand and no competition for the message.
Second best are the ones a competitor has been running for months and you have not. Someone else has already paid to prove that argument works on this audience.
Last are the ones everyone runs. You can still win there, but you are competing on execution rather than on the idea.
Write it down before you make anything
The output of this is not a mood board. It is a list of arguments, each with the evidence behind it and the specific thing you expect it to beat.
Doing this before production is what separates testing from making ads. Without it you will produce volume and learn nothing, because you will have no idea what each ad was supposed to prove.
We also wrote about what happens when an account runs one argument for too long.
If you want to see what this looks like on your account, we build the first batch free. We research the market, your customers and your competitors, then make 40+ static ads and test them. You get them in 24 hours.