Banding Sliver - No Symbol (CMB2) from Mystery Booster Playtest Cards 2021, available at 401 Games Canada.

• Rarity: Rare
• Finish: Normal
• Artist: Alicia Mickes
• Card Text:
  All Slivers have banding. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature’s combat damage, not its controller, among any of the creatures it’s being blocked by or is blocking.)