I see a lot of ad hominems on Twitter. Also countless faulty/hasty generalizations ["Everyone I know experiences X, so everyone must experience X."]

strawman and slippery slopes are the most common

lots of ad hominem, and enough strawmen to uh, make a straw mob

I don't know logic, but what inhahe said is pretty common

The most common logical fallacy I see in the wild is confusing "if X then Y" with "if Y then X" or "all X are Y" with "all Y are X". Another one I see a lot, particularly in the news, is assuming correlation is causation.

Sunken cost fallacy. There's a lot of ppl in my life unhappy with where they are but they're too afraid to make a change just because they've already put so much time into it

That coincidence in time is the same as causality.