The Beverly Hillbillies is on CHCH in Toronto at 11:00 am on weekdays now. They showed that episode just a few days ago.
I remember Joi best from the episode of Superman she was in, where she “married” George Reeves. I couldn’t have been any older than six when I saw it for the first time.
The 1970s Mickey Mouse Club had a couple of crushes for my 9 year old self. I can’t remember now, but I believe I liked Kelly and Allison.
Took me a long time to really notice girls, maybe because I have seven older sisters. I don’t remember crushing on anyone until the third season of “Three’s Company”, which puts me right at the OP’s cut off. There was another crush a few years later but that’s a different thread.
None that haven’t already been mentioned.
I think my weirdest one would be that cougar that was always after Jack tripper in three’s company.
Susan of “Susan’s Show”, when I was 6-7. "Susan Heinkel" Pictures and Photos - Getty Images
Mouseketeer Cheryl, “The Mickey Mouse Club”.
Janet Lennon, of the Lennon Sisters.
Mary Ann from Gilligan’s Island when I was really young.
Lynda Carter, Wonder Woman
Donna Summer looked great in “Thank God It’s Friday” which got me through puberty in 1978.
Singer Annabelle Lwin of Bow Wow Wow from the I Want Candy video when I was in high school.
Betsy Russell looked great in a few films from the early 80’s (Private School, Tomboy, Avenging Angel and an A-Team episode!!)
The best may have been Susannah Hoffs of the Bangles…she looked spectacular in the Eternal Flame video!!!
Suzanne Somers was certainly nice. But I preferred Lydia Cornell who played Sara Rush on Too Close for Comfort.
Joi Lansing was amazing. Her appearances on The Beverly Hillbillies were quite amusing, for the absurdity of a 50-something hillbilly (albeit legendary musician) with a wife that young and beautiful, and for a woman built like Lansing having the surname ‘Flatt’.
She had another memorable appearance on Petticoat Junction as a rival to Betty Joe for husband Steve’s affections.
A close competitor to Joi was Sue Ane Langdon. I know I saw her on Dick van Dyke and McHale’s Navy in the '60s, but I remember her best as Herschel Bernardi’s wife in Arnie in the '70s.
“Lana Shields,” played by Ann Wedgeworth. I’m surprised to find she was 45 when she appeared in Three’s Company. I always thought she was maybe ten years younger than that.
Marina from ‘Stingray’.
Joan Collins.
Probably Marlo Thomas - That Girl, and Karen Valentine - Room 222.
Honorable mentions to Joey Heatherton (perfect sleeper, anyone?) and Ann-Margret (presumably from variety shows).
I’m pretty sure cigar and mattress ads played a BIG part in my youthful appreciation for televised sports…
Though I was a young adult by the time the Bangles were around, I heartily agree with you! The 2:47 mark in this video is what drove home that crush for me.
David Cassidy - The Partridge Family
Davy Jones & Peter Tork - Monkees
Randolph Mantooth - Emergency
Alan Osmond (not Donny!) - The Osmond Family
Burt Reynolds
Michael Landon - Bonanza
Ted Bessell - That Girl
James Brolin - Marcus Welby
Don Grady - My Three Sons
Michael Cole - Mod Squad
I forgot -
Michael Gray - Shazam
Bill Hudson - The Hudson Brothers Razzle Dazzle Show
Bert Convy - Various game shows
I had a lot of crushes!!
Burt Ward (Robin on Batman)
Bobby Sherman (Here Come the Brides)
Michael Landon (only on Bonanza, not later on)
I remember having a huge crush on Ann Jillian when “Jennifer Slept Here” was on the air. Looks as though I would have been 10 at the time.
In an episode of MTM, Lou Grant confessed to having a crush on Joey Heatherton. I remember her from this commercial and an episode of It Takes a Thief, in which (IIRC) she didn’t have much to do:
Joey sounds a lot like Ann-Margaret in that clip from Bye-Bye, Birdie they showed on Mad Men.
Where cigar commercials are concerned, no one beats Edie Adams:
I looked for the one where she sings “Hey, Big Spender!” in that red dress, but couldn’t find it anywhere. 
ISTR Angie Dickinson typified SEX for me, but Police Woman didn’t come out until I was 13, and she was a tad long-in-the-tooth by then.
Susan Dey, as _______ Partridge. She was so pretty, I can’t remember her first name on The Partridge Family. My heart melts, even today.