https://actions.getdrafts.com/a/113
I know Drafts has a built-in Find (and Replace) feature, but I wanted something more like searching for text on a web page in a web browser.
I hit ⌘⌥F which opens a search prompt. Tapping Find selects the first occurrence in the draft. If I hit ⌘⌥F a second time, it selects the next occurrence. And so on. After reaching the bottom of the draft, the repeated searches to start from the top again.
(I can skip the prompt by first selecting some existing text I want to find elsewhere in the draft)