Features I never use and wonder if I'm missing anything.

Hi AaronBurgessAU​ 

there is a great video by David Anderson: Using Lightbox Slides in Storyline | Articulate - Community

This may include some ideas for you to apply too?

The zoom regions I find helpful when making a gamification - walkthrough a specific order, looking at things closer etc. 

I use zoom with software simulation where  the user has to find a small zone on the screen or menu bar. I can show you if you wish just ask

I've never used the Zoom Region, either, though I see how useful it could be for software simulations (like Thomas mentioned), looking at maps, or similar situations. I have used the Zoom picture tool to allow folks to enlarge an image if desired.

I frequently use Lightbox slides. They're very handy when some information needs to be available from multiple slides. Just keep the info on one slide, and lightbox the slide from wherever it's needed.

For example, resources and/or the glossary can be put on a slide that's lightboxed from a custom Player tab. (See TIP: Create Custom Player Tabs for Your Resources, Glossary, and More | Articulate - Community )

Also, I've seen folks Lightbox the related slide from the feedback layer of a question. 

In my opinion, the Zoom Region is a somewhat underestimated feature in Storyline. While I don’t use it frequently, it can be surprisingly effective. Using a Zoom Region gives learners a close-up view of specific parts of a slide, helping to highlight important information.

By combining multiple zoom regions with images and carefully timed narration on the timeline, you can create dynamic and engaging presentation effects.

This technique can be used to tell compelling stories across a wide range of topics, with narration guiding the learner’s attention to key visual elements.

I’ve attached a simple example that introduces a few of the world’s most famous cities through a short, narrated interaction.

Nedim​   Totally agree with: combining multiple zoom regions with images ... to create dynamic and engaging presentations. 

AaronBurgessAU​  You might want to check out some of the e-learning challenges for creative uses:  lightboxes and zoom and magnify features.