These two creatures each need to go in a fairly specific build, but they are each fairly good, if somewhat niche cards
Then the two-cost uncommon instant will dig three and draw like a less digging Impulse
The second card (Angelic Shield) costs one white mana, mana produced by a plains, along with one blue mana, which comes from an island
There are loads of things that put lands into play and as such even without sac lands you can expect to be getting more than one mana a turn from your snake as well as the option to get involved in combat
But when used on a creature you control, you get to unlock its true potential
Scalable and/or X-spells are also great inclusions for decks that generate a lot of mana, as a late-game Crackle with Power, Burn at the Stake, Comet Storm or Urza's Rage can dish out such mighty degrees of damage that even Commander players quake in fear