If you take the ideas from the transclusion/inclusion discussion you could also extend table cells with simple references:
| Theme | List |
|-------------|----------------------|
| Shopping | :[grocery list][B2] |
| Programming | :[HTML elements][B3] |
[B2]:
- oranges
- bananas
- apples
- lemons
[B3]:
```
<html>
<!-- some code block -->
</html>
```