Which tag should one use so it could appear as news icon?
If you are just practicing and polishing your skills. Why not contribute to the pixelart community.
Consider making stuff 50 x 50 px max canvas size and include tags when submitting so they can be used for news item icons which we always need more of.
Subject matter is unimportant because you never know what the news item is about so really just add tags to what you make that's small.
Anything that matches the icon is fine.
Its just to find when making news posts.
For example, here it could be:
coffee, mug, drink, caffeine, etc.