All you need is a demon in play to draw cards and siphon life each turn, and you can even create one when you unlock Ritual Chamber
Japanese SAR cards range from approximately $50 for less popular Pokemon to $800+ for flagship chase cards like Charizard ex SAR from SV3 or Nanjamo SAR from SV2a 151
Some cards, like Mew and Gengar, still can pull $20 to $40 price tags but the versions are much more easily attainable through online marketplaces and tabletop game stores
Marcy: Recursive and annoying, the perfect encapsulation of a roach
Higure, the Still Wind Higure, the Still Wind from Betrayers of Kamigawa is a mono-blue commander on this list, yet tends to be more useful in the 99 because of its high mana value and lack of ninja creature support in mono-blue
In small amounts, Rad Counters can be beneficial, enabling graveyard based synergies