In no order, by no means exhaustive, and lazily copied from my following list, but these should surface a good deal of quality ML content on your timeline, both for the state of the literature, and for more speculative, forward-looking theorizing.
note: some, like Sutton and Sutskever, aren't terribly active, but they're worth following anyways since it signals to the algorithm which sorts of tweets to suggest
@nearcyan @arankomatsuzaki @ethanCaballero @_albertgu @lcastricato @tszzl @gwern @fchollet @drmichaellevin @Plinz @sama @sharifshameem @woj_zaremba @ilyasut @karpathy @RichardSSutton @RiversHaveWings @ericjang11 @_akhaliq @hardmaru
note: some, like Sutton and Sutskever, aren't terribly active, but they're worth following anyways since it signals to the algorithm which sorts of tweets to suggest