
Creatures you control with +1/+1 counters on them can't be blocked.
Herald of Secret Streams has 5 printings, first in Ixalan (2017). EDHREC ranks it #1,048 among Commander cards. It appears most in Hakbal of the Surging Soul decks (23,626 on EDHREC). 1 public deck on TCG runs it. It has 1 official ruling.
Deck counts from EDHREC.
Cards that show up in the same decks on EDHREC.