There is nothing stopping a player from using four of one type of V-UNION card, however, with the caveat they can not use the V-UNION form
The two closest comparisons that came to my mind were Gilded Lotus , which is another lotus that costs five and taps for three mana of a single color (without entering tapped), and Jegantha, the Wellspring , a five-mana creature that also taps for one of each color but with a restriction on how it can be spent
If you don't want your opponent's spell to resolve, you simply cast Counterspell in response
The last color is green the color of nature and harmony
The Pokemon TCG likes to refer to many different types of cards as Rare Ultra
Brawl Legal Vintage Legal Timeless Legal Commander Legal Pauper Legal Oathbreaker Legal Penny Not Legal Toolbox Notes and Rules Information for Explore: Explore's effect allows you to play an additional land during your main phase