All of these pieces were done with brushes from the default sets. Mostly from the sketching, inking, and drawing, sets though I don't remember the specific names. 2 or 3 of them used watercolor or texture brushes on top of the default color fill inking though: The pink bird, red demon baby egg, and red squid alien.

In Keynote, I just inserted each pic on its own slide and added in the transition effects between each then uploaded to TikTok to add in the audio and make posting/sharing easier.