Yep, you’re right. My granddaddy used to say “What in tarnation!” all the time.lol! Yep, I've heard those too, "Lands sake" is new to me though.
"Bless your heart" Is a phrase that always sticks out to me because it's like this backhanded way of saying "You dumba**" under the guise of sympathy, lol.
Exclamations specifically, I've heard.
"Hell's Bells!"
"What in tarnation?!"
"I do declare!"
"Well I never!"
And when coming from a lady a hand is usually pressed to their chest when they say it, as if their heart is literally going to hop out of their chest from their shock at someone's audacity.