The IG story effects gallery does allow for finding users in a way. You might not find a traditional user search bar like in other parts of Instagram. But, if you explore the effects, for example, some effects are branded with a user's name or profile link. Also, when you use an effect, sometimes there are related effects or users shown as suggestions. So, by interacting with the effects and exploring these suggestions, you can find other users within the context of the effects gallery.
Yes, it's possible to find users in the IG story effects gallery. There are often tags or mentions of users who created the effects or those who have used them in a popular way. You can look for these indicators to discover other users. It's like a mini - community within the effects gallery where you can connect with others who are interested in the same types of effects.