I used to do a pretty mean Johnny Mathis & Elton John.
(not at the same time.)
We have a friend who likes to play around on the phone, mainly poking fun at a mutual acquaintance. My SO usually talks to him but sometimes I pick up first and mess around with different voices.
(as Yogi Bear): “Jellystone Forest, Yogi speaking.”
(as Peter Lorre): “Igor’s Mortuary. You stab 'em, we slab 'em.”
(also Peter Lorre): “Igor’s Mortuary and Whorehouse. Do you have a stiff for us?”
(as Kermit the Frog): “Hi-ho! Kermit the Trump here. 
It’s not easy being orange…”
He didn’t get that last one.
My limited repertoire includes an impression of Peter Lorre, in particular an impression of actor Paul Frees doing his impression of Peter Lorre in the Spike Jones version of “My Old Flame”.
My old flame
I can’t even think of her name
…I’ll have to look through my collection of human heads
There’s not a lot of call for this particular talent.
When I was in Great Lakes, there was a recruit who did a dead-on impersonation of Chief Ambrose, our company commander. So good that I immediately froze; the chief had made me one of his special projects.
I do Dr. Ruth (Always pwactice safe sex!). My husband used to be able to do PeeWee Herman. That was a favorite with the kids in the neighborhood.
Boo-Boo: Gee, Yogi. Mr Ranger isn’t gonna like that.
Yogi Bear: Sca-rew Mr Ranger!
Back in the days of answering machines, my outgoing message for a while was me doing John Lennon.
I do a pretty decent Dr. Now (“My 600-Pound Life”).
Also, Henry Fonda as Norman Thayer (“On Golden Pond”).
mmm
Henry Fonda as Tom Joad (The Grapes of Wrath):
Reds, Reds, Reds. Everywhere you go nowadays, somebody’s callin’ somebody else a “Red.” Who are these “Reds,” anyway?
I did a good Cobra Commander.
Come to think of it, I’ve also been known to sing “Home on the Range” as John Wayne. Not on the phone, though, which is why I didn’t remember 'til now.
You guys can do Henry Fonda? Thats not as easy one…now Kate Hepburn… “You old fuddy dudddy youuu”
For some reason I always wanted to be able to do Walter Brennan. If anybody here does him, how do you approach him? I don’t think there’s much call for his voice nowadays 
Have you ever heard “The Prospectors” by Hudson and Landry? I can do Refe and Zeke so well I would never guess it’s me.
Boy, I couldn’t live like that!
I can do H&L’s eponymous Sir Basil and Sir Geoffrey too.
It’s settled, then. We’ll make it a foursome!
Walter is fairly easy. Just think “Cranky old prospector” and throw in a bunch of “Eeee-Hees” and “By cracky!”
Another oddball one I do that I don’t see much of is John Huston.
“Can’t die here! Can’t die there! Take care of ma bair, or I’ll haunt you for sure.”
For any voice I have a catchphrase*, or just a word, to trigger it.
For Walter, it’s his excitable side from The Real McCoys: “Luuke, Luuuke! The bahhhn’s on fahhhhr!”
Once I say that, and get my lips wide and my diaphragm pulled up tight, I can go on for an hour.
So when I do him, it’s this sort of thing…
“Well, now you young’uns don’ unnerstand…”
But ratcheted up nigh unta eee-leven, dad gummit!
.
*I assume that’s pretty common. George Carlin, teaching how to do Ed Sullivan, says his trigger is “Well now you know”… followed by “right here on our stage…”
Then there are some where you can hear them in your head…and SOMETIMES you can just grab them out of your skull and do them, but couldn’t on command so it would be kinda useless in a professional setting. Like:
Anthony Hopkins or John Mulaney, I can usually get Hopkins though. Or a version. He likes to flatten his hair over his head and I’ll say something like “Are you afraid to go round the Horn? Are you a coward?”
I’ve done a lot of voices in my day, but I’ve never been particularly proud of being able to do them… until my (then-tiny) kids wanted me to read the first Harry Potter book to them (when it first came out).
I did, and I had SO much fun figuring out the voices…
(“Let’s see, Dumbledore would be a James Mason… but not Lolita, more like Journey to the Center of the Earth. Hmm, more tired, so I’ll throw in some of Richard Harris’s breathy poetry readings…”).
Imagine my surprise when Jim Dale’s audiobooks and later the film characters’ voices sounded like mine. (They even cast Richard Harris after they heard me…)
I read the ‘Mistah Pottah…’ books everywhere we went, in mountain cabins and cross-country trains, and once the kids from another family joined us.
Then, my kids grew up and I had to read the last book to myself…
That sounds amazing. The only thing close to that I did was a teacher I knew had me record some lines from a kids book, so i threw in random 90’s impressions (This being 1993) like Gilbert Gottfried. I heard later the kids squeeled “Its the Aladdin Parrot!”
I like the snl “80’s audition tapes” cause everyone can break out impressions they havent used in 30 years like…Bobcat Goldthwait
Edit: That Harry Potter story reminds me…the bulk of my Alan Rickman impression is simply…“Pot-tah. Euuuu fuuuul.”
You start with “Gooood Gawwwd” as your base and work your way up to “I think I know how to build a fire fer crissake!”.
mmm
I used to do the Iron Sheik. “All you pipple shuh tup! Done say USA USA!”