The Doomskar is a phenomenon in Kaldheim where two different realms will crash together and kind of bleed together for a bit, which generally leads to open warfare between the two realms for as long as the connection lasts
You either reveal a Land, which you get to put into your hand, or you reveal a non-Land card, which you can either leave on top of your library or put into your graveyard
These care about specific words or letters that appear in card names, in rules text, and elsewhere
Eternal Witness: Eternal Witness is itself a 2/1 creature, but gets you an extra card from the graveyard
Mostly this is just a slightly different take on Angel of Invention, it is more bodies and more versatility in combat
Mid-tier casual cards like Gilded Lotus, which dropped from $15 to $3 with the release of Dominaria , are far riskier to own