>>715120846
Kuukiyomi 1+2+3
Okage
Kingdom of Loathing, West of Loathing, and Shadow Over Loathing.
Super Mariomon
Akiba's Trip series but only if you're familiar with most of the otaku references and jokes. If you're not into Gundam, Tokusatsu, Eva, the Big Three, and so on it won't be as funny.
Wattam but it's somewhat situational like Welcome Back Toilet.