You should get staple common and rare first. Pandora is never bad but only having 1 copy is very inconsistent (unless you pulled him from that 3 legendary offer), while time maelstorm is somewhat used in combo sajj, which is a expensive deck. It sees few use due how your general still takes damage anyway (unless falcius was played)
Gold is achievable through decent decklist with staple cards (for me, it varies between players but I think I got most of them here)
Lyonar : Lasting Judgement, Arcylte Sentinel, Sun Bloom, Ironcliffe Guardian, Azurite Lion.
Songhai : Mist Dragon Seal, Katara, Ki Beholder, Four Winds Magi.
Abyssian : Bloodmoon Priestess, Shadowdancer, Ritual Banishing, Darkfire Sacrifice.
Vetruvian : Pax, Falcius, Whisper of the Sands, Fireblaze Obelysk, Starfire Scarab.
Magmar : Young Silithar, Thumping Wave, Elucidator, Egg Morph, Flash Reincarnation, Earth Sphere.
Vanar : Frostburn, Snow Chaser, Hailstone Prison, Razorback.
Neutral : Primus Fist, Sojourner, Sunsteel Defender, Wings of Paradise, Blistering Skorn, Lightbender.