HiCoffee
A bargain of a caffeine tracker. Available only for Apple devices (including Vision Pro).
What I like about it
This is an absolutely brilliant app that can be purchased on a lifetime license for about 10$ or less (can't remember exactly, but it's a bargain). It allows you to track your caffeine intake with colorful and animated graphics and charts, allowing you to respect your limits and to go to sleep without the jittering. The developer updates it constantly and it also features both widgets and quick actions for the Control Center. I talk about it in my article on Caffeine Hacking.
What I don't like about it
It's available everywhere, but only as long as you have an Apple device. It features a default list of coffee and tea brands such as Starbucks, Costa or Pret for quick add, but it could be greatly expanded (e.g. doesn't have Nero from the UK). You an create and reuse your owns though, which is what I do.