Budget Alternatives to Khalni Hydra

Gargantuan Leech $0.04 7B · Leech This spell costs {1} less to cast for each Cave you control and each Cave card in your graveyard. Cinderslash Ravager $0.06 4RG · Phyrexian Warrior This spell costs {1} less to cast for each permanent you control with oil counters on it. Yavimaya Sojourner $0.07 7G · Treefolk Domain — This spell costs {1} less to cast for each basic land type among lands you control. Wildvine Pummeler $0.08 6G · Giant Berserker Vivid — This spell costs {1} less to cast for each color among permanents you control. Rime Chill $0.11 6U · Instant Vivid — This spell costs {1} less to cast for each color among permanents you control. Search Party Captain $0.12 3W · Human Soldier This spell costs {1} less to cast for each creature you attacked with this turn. Dargo, the Shipwrecker $0.14 6R · Giant Pirate As an additional cost to cast this spell, you may sacrifice any number of artifacts and/or creatu... Walking Skyscraper $0.17 8 · Construct This spell costs {1} less to cast for each modified creature you control. Stratadon $0.18 10 · Beast Domain — This spell costs {1} less to cast for each basic land type among lands you control. Sentry Bot $0.24 4W · Robot Flash Zagras, Thief of Heartbeats $0.33 4BR · Vampire Rogue This spell costs {1} less to cast for each creature in your party. Valiant Changeling $0.33 5WW · Shapeshifter This spell costs {1} less to cast for each creature type among creatures you control. Hamza, Guardian of Arashin $0.34 4GW · Elephant Warrior This spell costs {1} less to cast for each creature you control with a +1/+1 counter on it. Primeval Protector $0.68 10G · Avatar This spell costs {1} less to cast for each creature your opponents control. Hierophant Bio-Titan $1.89 10GG · Tyranid Frenzied Metabolism — As an additional cost to cast this spell, you may remove any number of +1/+...