So unlike a lot of other overlays, I want to keep things as simple as possible, but still give enough information to help make a decision.
These two overlays add a star rating to shows and movies, and a continuing icon to shows, add to a country age rating image and that's my subtle look for posters.
Each has a small amount of choice to tweak how it looks for preference (see the respective readme files, where the attached screenshots have a bit more context).
For the UK centric config I use:
libraries:
<name>:
overlay_files:
- file: config/kometa-subtle-status/subtle-status.yml # Remove for Movies
- file: config/kometa-star-ratings/star-rating.yml
- default: content_rating_uk
template_variables: # Move to the bottom-left
horizontal_offset: 30
horizontal_align: left
vertical_offset: 15
vertical_align: bottom
back_color: #00000000 # Transparent
back_width: 105
use_nr: false
Star Ratings: https://github.com/Rycochet/kometa-star-ratings
Subtle Status: https://github.com/Rycochet/kometa-subtle-status