No — none of these have a delete button in the current version, because orders and subscriptions refer back to them. Retire them instead:

• Plan: switch Is Active? off (stops new sign-ups everywhere) or Hide Entire Plan from Customer? on (keeps it available on POS and for existing subscribers, while hiding it from the customer subscription selection page). Individual price rows can be deleted with the trash icon.
• Meal Pack and Credit Package: switch Is Active? off; there's no separate "hide from customer" toggle for these two, so turning a pack or credit package inactive is the only way to pull it off the site while keeping it in the admin list.
• Plan Groups and Funnel Reasons are the exceptions: groups can be deleted (a soft delete — the group is marked inactive and deleted behind the scenes, so it stops appearing anywhere), while reasons only have an Is Active? toggle and no delete option at all.