I think these combos don't work. With these combos I mean mashing a "transfer control on etb" creature with a "etb downside" creature. The other example is in the quote above. It does not work with neither gilded drake nor akroan horse. Joined with phage the untouchable or leveler, they etb as one creature, putting both effects on the stack. You can decide which resolves first, so you might pick the change controller effect, which resolves, but afterwards the other etb effect resolves, emptying your library or making you lose the game. This combo would only work, if there was a creature that says something like "This creature enters the battlefield under control of target opponent".
Impressive how none of these 3 examples work.
I think these combos don't work. With these combos I mean mashing a "transfer control on etb" creature with a "etb downside" creature. The other example is in the quote above. It does not work with neither gilded drake nor akroan horse. Joined with phage the untouchable or leveler, they etb as one creature, putting both effects on the stack. You can decide which resolves first, so you might pick the change controller effect, which resolves, but afterwards the other etb effect resolves, emptying your library or making you lose the game. This combo would only work, if there was a creature that says something like "This creature enters the battlefield under control of target opponent".