There was James Doohan, Walter Koenig, George Takai (I don't remember how to spell his name), Majel Barrett, and Grace Lee Whitney. The last one's birth first name was Mary, and I don't remember her full name. True, a lot of those didn't appear in the opening credits; but Deforest Kelley did. I read about how that was the first time William Shatner and Leonard Nimoy had been on the small screen for TV since Star Trek went off the air. What's strange is that I've read that Nimoy and Shatner didn't get along very well back in the 60's for Star Trek, but this was William Shatner's show, and he chose Leonard Nimoy to be on an episode with him.
Take care and God bless you