Some sample customizations or modifications required.

My dear Axaptians. I hope you guys are doing well. I need a small help from my fellow axaptians. I am searching for some example customisations or functionalities in ax 2012 or D365 FO, for enhancing my concepts. If you guys might have worked on any customisations where you got to learn something new. Or perhaps where you got to customise some standard functionality of AX, then please be kind to share. You can also share a link here if you might have already written a blog about it somewhere. This is just a fellow technical axaptian trying to sharpen my knowledge about the tool. Thanks so much in advance.