In the past, low level monsters were often frowned upon unless they had a destructive effect like Man-Eater Bug. When Konami took over Yu-Gi-Oh! from Upper Deck Entertainment, the power creep rolled in fast and now swarming the field with low level Monsters has become a massive advantage booster.
A few examples of low level monsters at their best include the frog and plant engines. Refer to lesson 5 and lesson 11 for more information.
A few reasons for why low level monsters become a huge advantage is the increased ability of swarming.
Another example of low level monster that have taken the spotlight are the Ojamas. With cards like Ojama Country and Ojamas Red and Blue, Ojamas have, since their creation, increased in effectiveness and are winning more than ever.
Level 2 or lower monsters also have access to even more support from cards such as Graceful Revival, Junk Synchron, and Doppelwarrior to increase their effectivess at swarming.
Overall, do not forsake the little guys because it is they that hold all the cards!