You can use Instagram to show a collection of collectibles. You can create a story with types or time stamped when you got it list. This can be helpful if you need to have an insurance investigate loss or damage.
You can also use it to show others on your Instagram or Facebook account what you have in your collection.
If you are going to sell items you can sell them without selling them. In other words by showing others you will say to them this is important to you and if they desire one they can get it from you but it will cost because how could you part with it Interest can spir need. And if you are showing it on the Internet it will get likes and comments. All you have to do is let it be known that you like it but you are really interested in another item then you will probably get a higher offer than if you sold it on ebay.
Also it can help build your reputation as a collector and an expert in this category. So put your stuff in your Instagram account and connect to others and enjoy the discussion.