Yes. In fact, we frequently have sellers who bundle multiple websites and domains under one package. The price depends on how much the websites make together as a whole.
You can also offer add-ons (Training, Private Blog Networks (PBNs), etc.) to a package to make your listing more attractive to potential buyers.
Keep in mind that some websites are better bundled together while others are not. During the vetting process, we may request that some of the websites be broken up due to our belief in how easy they are to sell, but it’s ultimately the seller’s decision.