As mentioned above: Play Nightwatcher. There are not many rush minions, but those that exist are played frequently. It's a great way to stop this unblockable source of damage. As a bonus, you get free wins when you face obelysks.
For maximum effectiveness, play Argeon and make this a 4/4 nightwatcher. And then give it aegis.
Another option is to play way more conservatively. The largest mistake I see people make in this game is to hug the other general with your own. This only works out for one of the two players. When you face a deck that can swing lots of life points through heal or damage from hand (see: rush minions), then it will favor them. Distance yourself as much as possible from the opposing general. It is a bad idea to hug Abyssian, Lyonar and Magmar. Generally speaking, it is a good bet to hug vetruvians, vanar and songhai. Especially if you are playing your magmar deck. Adapt based on what your opponent is bringing to the table of course.