Can I group articles visually?

Yes. Under Grouping in the More (three-dot) menu at the right of the header, By feed puts each feed's articles under a heading with the feed's name, and By date splits the list into Today, Yesterday, Previous 7 days, Previous 30 days and then the months and years before. None turns grouping off.

Group a list

1. Open a folder, the Newsfeed or a tag. For By feed in a folder or the Newsfeed, switch the list to Unread.
2. Click the More (three-dot) button at the right of the header.
3. Under Grouping, choose By feed or By date. Inoreader keeps the choice for that folder or tag.

An option that doesn't apply to the section you're in is greyed out, and hovering over it tells you why. Search results have no grouping, and in Read later and Archive By date saved (By date archived in the Archive) needs Newest first or Oldest first, while By feed also works with Source (A to Z). The video shows the menu in use.

Group by feed

Each group starts with the feed's icon and name, which opens the feed, and the feeds are ordered by their newest article. Between two groups, Mark above section as read marks the feed above as read, including its unread articles that aren't shown. By feed is offered in folders, the Newsfeed and Annotations while the list shows Unread articles, and in tags whether you view unread or all articles. In All articles mode the option is greyed out, and a single feed has nothing to group by.

Group by date

The headings follow the date Inoreader received each article, even with Use published dates on. Read later groups by the time you saved an article and the Archive by the time you archived it, under Today, Yesterday, Earlier this week and then the months, while tags group by the time you tagged it and Recently read by the time you read it. By date works almost everywhere, but not in Trending and not while the list is sorted by Magic, one of the sorting options.

Grouping per feed and folder

Inoreader saves grouping for each feed, folder, tag and section, and choosing it on a folder also sets it on every feed in the folder, as it does for layouts. New accounts start with None, and Reset custom grouping under Preferences > Account > Reset account, next to the other display settings, turns grouping off everywhere again.

Show saved articles first

In the same menu, Show saved articles first puts up to five recently saved articles at the top of the list under a Saved heading, with the rest under Latest. It works in the List and Card layouts.

Plans

Grouping works on every plan.