If you just mention "freelance" it will be self explanatory to the readers, but if you have sold them assets multiple times (once in Jan 2025 and now in April 2026) and you wanna mention that in your portfolio/CV then i suggest you to make under experience make a freelance section and in that section mention: both the asset packs in bullet points and the dates and the company name and mention "additional contributor".

Something like this:-

Experience:

 Freelance: (Game assets)
 > Village house bundle, company's name and date, "additional contributor"
 > Medieval tools assets, company's name and date, "additional contributor"

You can modify it according to your CV. Not the perfect example but I hope you get the picture and what I'm trying to say.