zard x is a prime spikes abuse candidate as its checks (heatran, slowbro, hippowdon) are ground-bound. the standard dd/blitz/dclaw/roost set is a tough match-up for any stall without a quagsire or slowbro, as flare blitz can overpower a hippowdon or gliscor easily.
you want pokemon that can pressure those checks offensive and switch into them defensively. also, hazard support AND control are both musts.
the spiker will either be klefki or ferrothorn. skarmory is decent too.
in terms of the offensive core, you'll want to pressure heatran/slowbro/hippowdon. heatran is easy to lure and wear down with team-specific choices like knock off clefable or knock off serperior or earth power celebi. starmie is really nice for zard as it spins (very important) and is pretty much a foolproof switch into heatran lacking power herb solarbeam. and those are much less threatening to the zard. some good offensive partners are serperior and manaphy.