I like the text selection feature of Telegram on iOS:
Long press on a message it gets focused you get context menu, and you can select it’s text, you can also scroll it when it does not fit on the screen.
It can be seen in their announcement on Replies 2.0, Adjustable Link Previews, Name Colors and More (they also use it for partial replies, we also have a feature proposal for this feature: Partial replies in DeltaChat desktop)