Vivillon

Vivillon has a valuable niche within the 1v1 metagame due to its access to the combination of Sleep Powder and Compound Eyes. This allows Vivillon to become the fastest user of a reliable sleep move in the metagame, letting it shut down virtually any foe that it can outspeed, including some of 1v1's most prominent threats such as Magearna, Mega Gyarados, and Magnezone. Vivillon also has access to a strong STAB move in Hurricane, which with Quiver Dance and Sleep Powder allows it to defeat Pokemon slower than it, such as Aegislash and Mega Altaria. However, it faces a lot of competition from other sleep Pokemon such as Jumpluff and Mega Gengar, all of which are faster and can cover most of the 1v1 metagame. Despite this, Vivillon can be considered to be better due to a more accurate Sleep Powder making it more reliable. Vivillon struggles against Rock-types like Golem and Crustle that carry multi-hit moves such as Rock Blast, leaving it unable to do its job effectively. Lastly, extreme frailty on top of a horrible defensive typing and a mediocre Speed tier leave Vivillon vulnerable to the plethora of Fire-, Electric- and Flying-types within the tier such as Mega Charizard, Zeraora, and Mega Pinsir.