Hi @Cykablatta,
Well, a texture atlas traditionally shouldn’t exceed 4096, though with Virtual Texturing (which actually works really well in conjunction with atlases because of the way it loads samples), you can expand this limit.
Assuming the traditional 4096 limit, the amount of standard textures you can fit in is relative to your required texel density. If your asset textures need to be 1024 to retain maximum quality, then you’ll only be able to fit 4 textures in.
However, the more common version of texture atlasing is to use variable texture sizes. This allows small 128 decals to exist within the same atlas as major assets. Generally with this method, any hero assets should not be atlased.
If you have access to any of the Marketplace Polygon asset packs, you can look at their main texture atlas, as it’s a great example on how to get the most out of a single texture.
Here’s a good video that goes into how to determine your texel density:
Good luck! Let me know if you have any more questions.