Cryptic and short answer, but yes. Mostly related to "mispriced" volatility in equity options and it ain't retail - you need to be fairly quick and have some real $$.
Arb. vol. products themselves - mostly trading the term structure and again quick and $$.
Not options directly, but convert arb. still has decent following - most arising from the lack of transparency in the market.
Another huge arb. done mostly here in Chicago and not options directly is CME futures and a bit of their options against the correlated ETFs. Getting more crowded all the time, because there is still decent $$ in it.
Mostly as things have become more multiply listed and electronic - the opportunities have become fewer.
Merger arb. still has a following, but too much risk for many.
Plus it doesn't always work - things that get out of whack can stay out of whack for a long time.
Probably more, but these are the ones we focus on.