A thousand ways to break Merieke Ri Berit (Tiny Leaders)

Please let me know if you know more ways to break Merieke than the ones listed below!

Here are some ways to abuse the ability:
A) Captured creature is only destroyed if Merieke untaps but you do not lose control of said creature. Cast indestructible on it to keep it around for a while.
B) The "destroy that creature" is a triggered ability that can be countered with Stifle type cards. Put them under an Isochron Scepter for recurring uses.
C) If you end your turn with Sundial of the Infinite while the "destroy that creature" trigger is on stack the trigger will be exiled and you get to keep the creature(s).
D) If you untap Merieke while having her ability on stack you can steal another (as many as you like) creature(s) because none of the "gain control" with the bolted-on "destroy that creature" triggers have not resolved. Once they start resolving - and you gain controls of creatures - Merieke will be in the tapped state and for each trigger the game checks "has Merieke untapped since I gained control of this creature" and the answer is always "no" because you did the untapping before gaining control of all creatures. You can use multiple untap sources to achieve this or a multi-untapping device like Umbral Mantle or Crab Umbra. Leave her tapped at the end and you get to keep all creatures you stole in one go.
E) Finally the most powerful way: flicker (blink) the stolen creature. You have to do this with a card that returns it under your control i.e. Ghostly Flicker or Cloudshift. This creature is now a new permanent not related to the previous one stolen by Merieke so it's actually free of Merieke entirely!

Once Merieke untaps it will trigger for all creatures stolen with Merieke (except flickered ones) meaning you'll most likely lose them unless you perform the same steps again everytime you untap.

Note that Merieke leaving the battlefield will trigger the "destroy that creature" trigger and you will lose control of all creatures you took with Merieke. Your opponent will regain control of their own creatures but they will be destroyed once they hit the opponent's side of the table as per the trigger. (Except flickered ones. You get to keep them.) This is because gaining control is a static effect that ceases immediately as a state-based action and "destroy that creature" is a triggered ability that just goes on the stack normally. If the opponent has a card that can only target their creature they'll be able to target the stolen-now-again-their creature in the brief window when "destroy that creature" is still on the stack.

Keeping Merieke alive is one of the harder things to do, watch out for that.