Since Mirri, Weatherlight Duelist has first strike, you dont have to worry as much about attacking with it to benefit from its abilities
On the other hand, the Instants offer some great support by Bile Blight killing a board of tokens (this will obliterate Tyranid players), Dark Ritual helping to cast things earlier in the game, and Brainstorm helping you smooth out future turns
Many of the early games focused on retrieving magical, elemental crystals to defeat the villain of the game or restore order to the world
Cards that make tokens when you cast instants or sorceries like Sedgemoor Witch are perfect in this situation
Synergy with flickers and discard payoffs like Tinybones, Bauble Burglar, Entropic Battlecruiser and Waste Not, then backed up by counterspells and alternate plans like control, reanimator and wheels
Prices are an average from sites like echomtg, MTG Goldfish, and TCGPlayer