Hi @M_Tomy ,

I don't see any direct way but you can track it by periodically review against OOB features. Although During upgrades - skip items and upgrade monitors may help you in tracking it. Also Health scan checkup will provide you a report that what was customize and whether it was as per best practice or not. 

If my answer helped you, please makr it- solution accpeted. It will help future Readers as well.

Regards,

Nikhil Bajaj