From the site GCU linked to where you downloaded the font or element. There will always be a statement on the site which indicates the TOU for all items or on the individual download page for each freebie - when they differ one from another.
 
For example: GCU posted this freebie: https://gcucommunity.com/2018/06/20/freebie-wednesday-birthday-monsters-graphic/

 
When you click on the GCU link provided it takes you here: https://www.creativefabrica.com/product/birthday-monsters/
 
That element's download page clearly states: Lifetime licence for personal and commercial use. So you would provide the review team this link in this case: https://www.creativefabrica.com/product/birthday-monsters/

Hi Jacqueline,  
 Just want to chime in here with a quick tip on downloading graphics. First, I have a separate folder for the links to the TOU page of the design sites I buy from and get freebies from frequently.
Before I even download, I copy and paste the url of the design kit and add the date I downloaded it. This goes right into the folder with the graphics so I never have to search.
I learned when leaving notes to reviewers to check the link to see if it is still valid before submitting. This saves them the time so they aren't the ones to find out if a link is no longer active and they don't have to contact you regarding that at least.
I use one site so far that removes graphics offered after a period of time. This is where the date acquired comes in. I can then let the reviewers know that I got the graphic with a complete commercial license, the date acquired and that the link is no longer active.  
Hope this helps save you a bit of time.

Thank you all for the great tips.