Sparring Regimen is a rare Enchantment card from Strixhaven: School of Mages Promos (PSTX), collector number 29p. Current market price: $0.26 (foil $0.48), TCGplayer market prices via Scryfall.
When this enchantment enters, learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.) Whenever you attack, put a +1/+1 counter on target attacking creature and untap it.