Accidentally pos'd. I'm on my phone. Fairy wind is better since it'll destroy Tool and Skill Drain and whatever else is face-up. But on the subject Qliphort, Black Horn and Warning will be good against them because in the tcg they can used on pendulum summons of multiple monsters.
Basically the only way to deal with Killer is to prevent it's summon. Once it hits the board it's really hard to deal with. Metaion isn't a good enough answer for it since Skill Drain is a card plus you'd have to have a way to negate its summon because it'll most likely find its way back out. Sephylon can brick hard as fuck but most definitely answers it. Cyber Dragon is mehh because like it was said playing 1 card to deal with only 1 card out of 40 is bad yugis plus where is anyone finding room in the extra for Chimeratech? I wouldn't play Injection Fairy Lily since Solemn Advice will probably be a 3 of in all decks and LP isn't infinite. Solemn Advice's versatility makes it probably one of the best cards against the deck but it makes MST infinitely better going 2nd. You could also play the OG Horn of Heaven and ideally tribute off BA monsters to get their effects. It's never ideally summoned turn 1, so I believe negating its summon is the route you should go in dealing with Killer rather than trying to deal with it after it hits the board.