MonsterCardTooltip extends monster card tooltips so they show the monster category, description, location, and, most importantly, whether you already have the card or not. It supports the new monster card stats introduced in Chapter 3 (RoM Client 3.0).
If you also have (awesome) Advanced AuctionHouse (mantained by Mavoc) installed, you can search the AH for card you don't have! To do this, search Monster Cards in the AH and filter for !Learned (note the exclamation mark, it means "not learned"). AAH will only show cards without the word "Learned" in its tooltip.
Note that you need to update to MonsterCardTooltip v1.2 for this to work in Advanced AuctionHouse 2.7 or later.
vyCardInfo by vaily
This add-on is derivative work based on vyCardInfo by vaily. Basically, I removed the features I didn't want and stripped it down to only the tooltip extension. vyCardInfo does this and a lot more. If you want a full-featured add-on, go download vyCardInfo. If all you want is to know whether you have a card that a guildie just linked in chat, this is your add-on.
Can I do this? Yes. vyCardInfo and it's source code are public domain. I can copy, modify, and distribute it to my heart's content. All my add-ons are also public domain, so feel free to do the same.
Reporting problems, feature requests
Please report any problems or requests by creating a ticket at CurseForge.
Not in your language? You can help translating this add-on.
Tested in RoM client version 18.104.22.1689.