"Catch a glimpse of" is a commonly used idiomatic expression that refers to seeing something briefly. There are several synonyms for this phrase that can be used in different contexts. One of the most commonly used alternatives is "get a sneak peek" which connotes the notion of seeing something before it is officially released. Another option is "spot," which is less formal than "catch a glimpse" and is commonly used when referring to quickly seeing something in passing. Other synonyms for "catch a glimpse of" include "glimpse," "get a glimpse of," and "take a quick look at." Ultimately, it depends on the context and tone of the sentence to determine which synonym is most appropriate to use.