If you don't want to unsubscribe or roll-up an email then you can keep a subscription in your inbox by clicking the Keep In Inbox button on the mail list.
Emails from this sender will continue to land in your inbox. You can always change your mind and unsubscribe or add to a Rollup later!
Adding “keep in inbox” senders to a Rollup
To add senders that are kept to Rollup you need to click the "keep" button again to disable that option and then you can select one of the others.