"Beside" is a preposition that indicates the proximity of one thing to another. It is commonly used before nouns to show the relationship between them in terms of position or comparison.

what terms are commonly used for footnotes and endnotes

terms of analogy

Gold, silver, and plastic.

The preposition "of" is commonly used with the adjective "similar" to show a relationship or comparison between two things. For example, "The new model is of similar design to the original."