If the creature is no longer on the battlefield at that time, use its power from when it was last on the battlefield
For Blessing of Frost to work its magic, you want to be playing cheap creatures with power and sizeable three-drops, trying to close the game quickly, and only playing basic lands or Faceless Haven
If youve played a deck that features a lot of characters then song cards will always do well, as having a couple of exerted characters open to enemy attack, but still having a flush inkwell because the songs were played without cost is a strong place to be
Consider these different deck theme types for some inspiration
Orthion, Hero of Lavabrink In addition to having massive amounts of text, Orthion, Hero of Lavabrink is a strong card with the right support
At some point in time it became 60, but that some point in time was more like two points in time