Have you obtained the appearances of those items, Cleric?
If I had to guess, the collections tab is showing you the appearances that you would have available if specific criteria was met. So for the holiday hat, it needs to be the holiday for you to use it. The engineering, you need a point in engineering to use it.
For the Earth Warder appearances, you need to acquire the base armor appearance before you can use the additional visual effects.
I’m not 100% on that, and I’m seeking some clarification, but that is what it seems like to me. I know you said you had the base appearances of what you are trying for, but to be more specific… which pieces do you believe you should have? The name of the specific appearance would help. The screenshot shows the Draconic Hierophant’s Archcowl, do you have the base appearance for that one or are you referring to the Obsidian Gladiator’s Silk Hood?