spiders (arachnophobia) or of confined spaces (claustrophobia) is comparatively widespread. But there are also very specific “phobias” that most people have probably never heard of. One example is hippopotomonstrosesquippedaliophobia — fear of long words. This term, by the way, is an Internet hoax. The underlying condition is sesquipedalophobia.
Here is a detailed list of medically recognized phobias and those mentioned in popular science and similar sources:
https://www.bionity.com/de/lexikon/Liste_der_Phobien.html (retrieved 10.6.2022)