Ixtun Svetya

The main game plan is stall early. You definitely have the potential to win with vargo or rizahn + palace, but you should outscale pretty much anything if you can get a svetya down without instantly losing. At that point, even your merchants are 8/8 aegis units, and there are very few decks that can 1 for 1 that sort of card. If you can get a martyr's chains to stick on top of that, it's pretty much guaranteed gg.

Specific interactions: honor of claws + privilege of rank is amazing. Both cards are worth playing on their own, but if you discard privilege with honor, you get net +3 card advantage for 4 mana, while playing each card individually is net +2 card advantage for 7 mana. If you have both in your hand, passing turn 3 and then discarding privilege on turn 4 with honor is better than playing both on curve, even if you have nothing else to do on turn 3.

Vargo ignores harsh rule (including friendly harsh rules). You can potentially force your opponent to overcommit to the board in order to get past vargo and then get an easy 2 or 3 for 1 with harsh rule without killing your own board.

Merchant for stormhalt knife is a staple vs aggro. If the aggro deck can't reduce you below 10 health in a reasonable amount of time, then you should still win despite "wasting" your merchant. If they do manage to drop you low, a 0 power 5/5 relic weapon can do a great job of stabilizing you.