List of objects with Focusing Decor & ways to improve Focus

If your sim has a relatively high logic skill, I think it's from level 6 or 7, playing chess will give them a focused buff as well. I think the buff is called "a great move" or something along those lines.

I don't think anyone has mentioned elements yet. I often put an elemental display rack in the study and put some elements in it and then enable their emotional aura.

I'm pretty sure that using the archaeology skill and the research and debate skill can also give focused moodlets.