Is there a limit to how many different champion units can be included in a single deck, as long as each type is limited to 3 copies?

Ruling: There is no limit to the number of different champion units you can include in a deck. You can have as many different champion types as you want, as long as each champion unit has one of the two runes associated with your Legend and you don't exceed 3 copies of each specific champion.

Nuances:

• This differs from Legends of Runeterra which has champion limits
• Champions must still match one of the two runes associated with the Legend in your deck