Used to use all these other things like tell me when, weak auras makes a lot more sense.
You could literally remake your entire UI just using weak auras if you felt like it. Its an amazing addon.
I love weak aura's too but it is a hug memory hog, not really optimal for redoing you whole UI. When I was making trink and spell notifications I def could tell when Weak Aura's was being used in 25 man raids.
TellMeWhen is just an (imo anyway) easier version of WeakAuras. So depending on how good you are / how much time you're willing to spend, you can take your pick from those two. Both can track basically ANYTHING and be dragged and dropped on your screen with shiny colours etc. in countless ways. WeakAuras somewhat more than TellMeWhen.
There is a thread somewhere with about 5000 different weakauras for warlocks but if you just need basic tracking you can find some that I uploaded to my pastebin as a backup source (these do not reflect new trinkets from this tier, I haven't updated the pastebin in a while)