I had bought a bunch of these LEGO display cases the last few years:
Wanting something a little nicer that also held more, I saw a lot of custom stuff online, but they can get awfully pricey.
What I found aren't acrylic, so I apologize for going semi off-topic. Thought it might be helpful for anyone wondering about these.
I ran across these cases at Michael's that were cheaper than the LEGO ones above (almost always on sale <$30):
https://www.michaels.com/studio-decor-keepsake-display-case/10227067.html
(Not my picture)
I do miss being able to see minifigs better in cases that were clear on all sides, but these do look more sleek/professional overall.
The shelves are set in place (can't remove/adjust), and they're deep enough that you can double up a back row. I can now display about 100 minifigs in the space of two of the LEGO ones in the first pic that held 16 each.
If you do that though, it can be a bit cluttered: