Objects of various sizes that are grouped together can be described as showcasing unity. Unity refers to the quality of being united or forming a whole. When different objects are brought together, despite their differences in size or shape, they create a cohesive and harmonious visual effect.
For example, if you have a collection of various-sized circles arranged in a pattern, the overall unity of the composition is maintained despite the individual differences in sizes. This concept is commonly used in art, design, and composition to create balance and coherence within a piece.
In the context of the question, the term "unity" would best describe the scenario of several different objects of several different sizes being brought together to form a cohesive whole.