Start with ads you’re allowed to reuse
The best reference is an ad you already own that worked. You know its numbers, you own its footage, and the question is simple: will the same structure sell a different product in your catalogue? Next come shared formats such as the unboxing, problem then solution, the POV clip and “three things I use every day”, which nobody owns. A specific competitor’s ad is the riskiest reference, because the parts that made it work are often the parts you can’t take: their creator, their music, their wording.
Blurbly rebuilds every shot with your product and writes a new script, but it can’t settle rights for you. Anything you didn’t make or license has to go: people, logos, slogans, music and the exact voiceover.
With a competitor’s ad, ask what you are actually borrowing. Usually it is an order of events: the problem shown before the product, the product shown working before the price. If you can write that order in one line, you may not need their video at all, because the AI ad generator can build an ad from the line.