The phrase "in various sizes" is correct and usable in written English. You can use it when you need to indicate that a certain type of object or item is available in multiple size variations. For example: "These shirts come in various sizes, so you can find one that fits you perfectly.".
He worked in various sizes.
The pattern, called Peking Pastoral, comes in various sizes.
It comes in various sizes from 6 to 9 inches.
They come in various sizes and architectural styles.
Pixels can be assembled in various sizes and shapes.
Available this fall in various sizes, for $2,500 to $11,000.
SAW devices come in various sizes but are generally measured in centimeters.
I love the desktop app, it’s always running on my Mac. Ludwig is the best English buddy, it answers my 100 queries per day and stays cool.
Cristina Valenza
Retail Lead Linguist @ Apple Inc.