For sure you can't make a trade of the licensed items. But you can do work for others that include the licensed images. However, if you use the same image for a second project or even for own projects, you need to relicense the asset.
Look here for more information on licensing: https://community.adobe.com/t5/stock/links-for-licensing-terms/td-p/11366788 (Disclaimer: As always with licensing, this is my interpretation of the rules. I think they are correct and advice is based reading and interpreting the license terms and on fair use for both the buyer and the artist/stock company, but I can not rule out that my interpretation is wrong. I'm not an Adobe employee)
Regards, Abambo Hard- and Software Engineer and Photographer.