I would love an additional option to select from a list of categories or topics for new lenses. If you for example are interested in technical stuff and you select this category for your lens you will get results from known websites that focus on technical topics. This way you don't need to name specific websites that lens has to use.
Those categories or topics could be examples like...
- cars
- video games
- technical
- art
- 3D printing
- smart home
- nature
- science
... and so on.
The problem I see with you having to name websites you want to use for a lense is that you need to know them when you create your lens. With categories/topics you would get results from websites you didn't know before but could be of interest to you.
An additional option in the lense creation where you can select one or more categories/topics would do the trick to include a specific set of websites that are known to focus on the topics you selected.
