This is a big topic.
I enjoy the Roger Corman/Vincent Price*/Edgar Allan Poe** films very much.
I also think that the cycle of films including I Was a Teenage Werewolf, I Was a Teenage Frankenstein, Blood of Dracula***, and How to Make a Monster is enjoyable, despite its evident limitations.
I have fun with the rock 'n' roll/drag racing movies of the 1950's, as well as the monster movies of the same time period.
I can get some laughs out of the beach movie series, too.
Some of the non-Poe films from Roger Corman are fun to watch. The Undead, Teenage Cave Man, and The Saga of the Viking Women and Their Voyage to the Waters of the Great Sea Serpent**** are odd enough to hold my interest. X: The Man with the X-Ray Eyes isn't bad at all.
Then there are all those hippies/motorcycle gang flicks of the 1960's, as well as oddities like Gas-s-s-s and Wild in the Streets.
I can't ignore the foreign films that AIP edited and dubbed, even if they did mess up the originals to some extent, winding up with things like Voyage to the Prehistoric Planet***** and Voyage to the Planet of Prehistoric Women***** (both from the Soviet film Planeta Bur), Battle Beyond the Sun (from the Soviet film Nebo Zovyot), Queen of Blood (from the Soviet film Mechte Navstrechu) and Voyage to the End of the Universe (from the Czech film Ikarie XB-1.) If nothing else, these gave me a look at the very interesting SF films made behind the Iron Curtain.
(In another category completely is What's Up, Tiger Lily?, Woody Allen's new soundtrack transforming a Japanese spy movie into an outrageous comedy.)
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*Who starred in all of them except The Premature Burial, with Ray Milland.
**The Haunted Palace, despite a title taken from Poe, is actually an adaptation of H. P. Lovecraft's The Case of Charles Dexter Ward.
***Which, if there were any justice in the world, should have been called I Was a Teenage Vampire.
****Greatest title ever.
*****Two different movies, although they share a very large amount of the same footage.