The various sites offering these asset packs have different license terms. Below is a less restrictive version which applies to all packs.

Purchase of an asset pack allows you to use it in any number of projects (including commercial). There's no need to purchase additional copies of the asset pack for multiple projects or multiple developers.
Selling or making the contents of the asset packs available to 3rd parties in any way is not allowed. These assets need to be part of a larger project.
Using asset packs to train AI models is allowed within the scope of the project only. For instance : you are making a game with top-down spaceships, and you've bought the spaceship sprites pack. If your game comes with generative AI to create more spaceships based on this pack, this is fine. Not allowed is making an AI model or tool with the goal of selling or sharing the model, the tool or its output (as that would effectively replace me).

For requests or further info, email me at :
greywinged@yahoo.co.uk