An ideal first deck would contain a majority of the mechanics that Lorcana has to offer while containing many different strategies to explore
You can use an item before or after you challenge another character on the table, meaning that you can cast a buff (an increase to a cards attack or defense) or a heal a character whenever you want during your turn
That's why Upheaval is such a bomb: there are virtually no ways to deal with it, and once it is cast you can end up with two to three creatures plus a land on the board while your opponent literally has nothing, and has a hand full of sixteen cards they need to discard down to seven
However, you could feasibly upgrade this deck into something thats much stronger as there are some really strong pieces here
If you have any way to gain life or Explore, you will start a chain reaction
Modern Horizons 3 has a bonus sheet full of these, and two were shown off at MagicCon Chicago: Laelia, the Blade Reforged and Priest of Titania