Verbb Wishlist plugin see if item is in specific list
You can pass a list type handle in the query like this:
{% set compare = craft.wishlist.item(entry.id, null, 'compare') %}

I had to look at the source code for the craft.wishlist variable to confirm what that's doing, though! The Wishlist docs on checking if an item is in a list aren't super-clear on this, but passing the list type handle in the query will fetch the first list that matches that handle for the current user. If you have multiple lists for that list type, only the first one that the query returns will be checked for the item.