That's right, both Unfinity and Edge of Eternities gave us Shockland reprints
P/T Set Number 509 Language Deutsch Legal Formats Alchemy, Brawl, Commander, Competitive Brawl, Historic, Legacy, Modern, Pioneer, Standard, Timeless, Vintage Rulings (6/6/2025) A creature attacks alone if it's the only creature declared as an attacker during the declare attackers step (including creatures controlled by your teammates, if applicable)
Fairgrounds Trumpeter's ability triggers if, at any point during this turn, a +1/+1 counter was placed on a permanent that you controlled as the counter was placed
I can only get the lessons that are in the first seven slots, because, at the time, players put 14-15 different lessons without any downside in their sideboard, so WotC limited it to 7 slots in best-of-one to reduce this strategys effectiveness