I find it kind of weird how "Yurusan!" has become something so connected to Kotaro/Black (so much so that Tetsuo Kurata even designed and sells a shirt with the word written on it), when a lot of henshin hero says it, especially in the older shows. It's in practically every Maskman episode, for example. ("Kiros -- yurusan! Aura Mask!" "Baraba -- yurusan! Aura Mask!")
But nothing can top Hoji's Engrish. "Okay, perfect!"
Let's not forget about Shurikenger.
Shurikenger's First disguise: "I am sorry! I already to you, I am a detective. Don't you believe me?! Well that's too bad. Attention, please.