This is official feature when player loot certain items, an announcement will be made. The announcement message just like announcement from Item Package. On Aegis server the config can be set on BroadCastingSpecialItemList.lua file. While on rAthena is db/[pre-]re/item_flag.txt, with flag value 16.
Then to make MVP Card will be announced when player loot it from monster, you need to list the Card IDs into that file then add flag value 16. You can MVP Card IDs easily by using this simple query from mob_db_re table, a table created by mb_db_re.sql.
SELECT m.`DropCardid`,16 FROM `mob_db_re` m WHERE m.`MEXP` > 0 AND m.`DropCardid` > 0;
You can simply export or select all the results, or grab it from here.
Once everything are set done, the result will be like on this video: