Grim Javelineer is a common Creature — Human Warrior card from Aetherdrift (DFT), collector number 89. Current market price: $0.06 (foil $0.09), TCGplayer market prices via Scryfall.
Whenever you attack, target attacking creature gets +1/+0 until end of turn. When that creature dies this turn, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)