Unless you make cards depending on both of them, and assuming you don't limit the number of named cards in a Deck the way I do, players might want to run multiple Celestias instead of a Celestia and a Luna
7 Mimicat A Tricky Cat When Maximillion Pegasus unleashes Toon World, you know hijinks are about to ensue
This is such an amazing card since, in a deck like Virtual World, it allows you to special summon any of your level 3 monsters for free
theft-permanent Card Tag Scryfall Tagger
Honorable Mention -Tearlaments Rulkallos (Tearlaments Kitakallos)- If "Tearlaments Kitkallos" was still in the card pool, she would have been a decent target for Armament, but probably not a strong enough one to make the card a staple
Probably nothing to worry about there