Use your own definition of “cheesy.”
I nominate Glen Campbell’s Rhinestone Cowboy.
Afternoon Delight
“She’s Having My Baby” - Paul Anka.
In college radio days we’d play an excerpt from this song with sound effects of a woman screaming in the background. Immature but fun. 
I’ll do my part by nominating Young Girl, the pederast’s lament. Dedicated to Traci Lords. I’m sure someone else will be along to nominate “Wildfire” and “Timothy.”
“Rocky,” my standard recommendation.
I am staggered by how many of these songs I own–all but two!
I, however, nominate Bobby Goldsboro’s Honey, which I don’t own.
Argent Towers is going to hunt you down. 
Islands in the Stream
Kenny Rogers and Dolly Parton
If you pay attention to the words, they sound like a bunch of random song titles strung together.
I vacillate between thinking thisthe cheesiest song, or the greatest piece of music ever created in Western Civilization. Perhaps it’s both.
Patches
Butterfly Kisses.
I have a cover of that, and a cover of “By the Time I Get to Phoenix” by the same group. Just a bit more tolerable than the originals.
The wreck of the Edmund Fitzgerald.
Oh, stop it with the “How DARE you?!” looks. Examine your feelings, you know it to be true.