F. One dot on the left
Each thread has at most one dot, always on the left. Red means it needs you, blue means new messages. Unread names are also bold.
A thread that needs you AND has new messages only shows red (it's bold too).
My pick
G. One dot on the right
Unread is just bold, with no dot. A red dot on the right means it needs you.
Bold alone is a quieter unread signal than a dot.
H. No marks at all
Unread is bold. Needs you turns the name red. No dots or tags anywhere.
Red text is easy to miss on the dark sidebar, and harder to see if you're colorblind.
I. Slack mention bubble on the right
Unread is bold, exactly like Slack. Needs you shows a small red bubble on the right, like a Slack @mention.
The bubble shows a number (1), which might read as a message count.
Home
The number box is gone in every option. A card's number shows inside that card on the board (e.g. Relationships: "9 people waiting on ur reply").