In a sense, there are no "bad" plots, just texts that don't have any good plot. If you can describe the plot, then it might need work to become a good plot, but it doesn't have some sort of negative value. Theme is the same way, if you can state the theme, then it might not be much, but it isn't going to have negative value.
There are specific, limited exceptions. For instance...well, I'll spare you. But those really bad plots and themse can't help you write better...if you need to be told not to do those things, you need help of an entirely different sort.
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It's been posted before, but it deserves to be posted again. Strange Horizon's Stories We See Too Often. Along the same lines: the Weird Tales submission guidelines, with more stories that get seen too often; and at the Nightshade Books Discussion Forum for F&SF, a discussion on what editors don't ever want to see again, which includes the phrase "elf intolerant."
Eh. So good writing can make a lousy plot good, and a good idea can really suffer under lousy writing. Have you seen the The Evil Overlord Devises a Plot?
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Well, one of those links does contain the words "I never want to see another story about intelligent coati mundis on the moon." Perhaps that might suffice... But on a more serious note, those links do contain a number of the more overused cliches, if that's the kind of thing you're looking for. I'd also add in Dianna Wynne Jones' Tough Guide to Fantasyland.
But if you're specifically looking for cliches, I think I'm rather alarmed. The old standards in tropes and races and themes and characters can be reassuring, can be well done, and presumably became standard for a reason. But I'm wondering how many people say "Gee. I need a telepath-- common? OK. And a vampire, but he has to be a sexy vampire. And an elf. A gorgeous elf. And stew! Everyone will eat stew! It's quick and easy to prepare on the trail, of course! Stew! Nourishing stew! And the elf and the telepath and the vampire are searching for the Power Moonrocks of the Oracle Heights Housing Development...."