A lot of the on-theme finishers (Meloku, Multani, Avenger of Zendikar, Rampaging Baloths, Primeval Titan) are at a high power level, which is great for convincing the power-max crowd to try it but awkward if you're trying to tone things down
Saheeli Rai is expensive mostly because she's a planeswalker card and she suffers from price memory (thanks to infinite "Copycat" combo which was ultimately banned from Standard)
Gisela, the Broken Blade Graf Rats Hanweir Battlements Mishra, Claimed by Gix Titania, Voice of Gaea Urza, Lord Protector Vanille, Cheerful l'Cie
As an enchantment, Search for Azcanta only supplies card selection, not advantage, and with Ramunap Red the likely best deck from Day 1, Im not sure how many of this card you can afford to play
Cards like Narset of the Ancient Way and Sorin, Grim Nemesis benefit from discarding a split card since it deals damage equal to the mana cost