As a certification book author, I've taken a number of certification exams. Here's the full list. Before 2010, I took a bunch of BrainBench exams as well.
Asside from my Java cert books, I've created study notes/references for a number of them. The most popular are:
AWS Developer Associate (2019)
AWS Practitioner (2019)
Core Spring (3.X) - this is old, but apparently people still use it
The below lists my certification journey and my impressions/suggestions for the exams.
Java OCP 17 (829)