I have an Antec Three Hundred Two case with a spot on the side of the case for mounting an 80 mm fan. I put an Arctic F8 PWM fan there, and haven't had any issues with overheating since.

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Another option might be something like the Evercool Python Fan.

It's an evercool python. This listing is sold out, but you may be able to find it somewhere else.

https://www.amazon.com/gp/product/B07HFHPQG3/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1