Kid Kong

Kid Kong was the biggest star ( arf! ) of Monster Fun, coming in as the first strip of the fisrst issue, and starting out as he meant to go on, causing havoc in his eternal quest for 'nana's, and being scolded by his human friend Granny Smith, a deluded old lady who bought her glasses at the same shop as Mr. Magoo,
He was created by the late, great Robert Nixon, and was his favourite strip to draw, next to Frankie Stein. Kid was immensely ( arf! ) popular, and was Monster Fun's marquee character, being based on a really simple, endlessly adaptable premise.
He also, like a lot of IPC strips, regularly broke the fourth wall, as here where he insults the whole human race:

Or here, where he offers his lunch to his creator:

'Nana's, as you can see, play a big part in Kid Kong, and reached a weird kind of peak, as in the episode where, apparently, Granny takes Kid to Bananas Anonymous to cure his addiction.
Don't have that episode sadly, but here's some other examples, showing Nixon's mastery of size, scale and physical comedy.

Frankie Stein

Probably the most loveable of Monster Fun's inmates, Frankie Stein must've been extremely popular with kids, as IPC seemed to use him everywhere.
Starting in Wham! in 1964, the eternal nice-guy monster was resurrected ( arf! ) in the Bronze Age in short-lived weekly Shiver & Shake, staying on when that mag merged with Whoopee! ( great news next week, chums! ), finally settling as honorary editor of MF, years before another green skinned creature took charge over at 2000AD.
Frankie went through several formats too, from the regular strip here, to newspaper style 'silent' piece Freaky Frankie and breaking the fourth wall strip Frankie's Diary, Frankie's Fun Feature, Frankie's Freaky Fun Page, Frankie Presents Ticklish Allsorts, as well as probably several hundred more. This guy was big.
Wherever he appeared, he was great, a likeable, kind hearted big kid whose anguished creator, Professor Cube, spent every issue trying to kill him. He was drawn by several different artists, but the most memorable have to be Ken Reid, the prince of darkness behind Martha's Monster Makeup, and here, Robert Nixon, whose style defined kid friendly '70's fun.