I personally like Tasha, the Witch Queen because it lets you play with your opponents cards, but Baba Lysaga, Night Witch works nicely for Halloween since it asks you to use your graveyard for value
You can't sacrifice Koma itself to activate its last ability, but you can sacrifice any other Serpent you control, including Koma's Coil
Theme Decks There are four Future Sight theme decks, each featuring cards from across the Time Spiral block
I suppose theyll also be good in decks with bouncelands, like Boros Garrison
Part of this was because we were in the middle of the Ravnica: City of Guilds block and were using creature types to create distance between the different guilds
Simic cards tend to reward players for taking basic game actions like playing lands, drawing cards, and casting spells, which makes it a powerhouse in pretty much any format, but especially Commander, which is all about ramp and card draw