This post is in no way going to spoil anything about Deadpool 2. We're not going to talk about story points, we're not going to talk about any specific scenes, we're not going going to spoil anything. This is a SPOILER FREE post.
That being said, we live in a world where Marvel Studios has made it common for people to stay through the credits of their favorite movies. Now, you should always stay through the credits of movies because every name on the screen is someone who worked hard to make the movie happen. There's also nice music to enjoy which is always fun. The merits of staying through the credits aside, fans have come to expect certain things from their comic book movies, and some sort of after-credits scene is certainly one of them.
Deadpool 2 hosted its first public screening yesterday in a similar way that they hosted screenings for the first Deadpool film back in 2016. After the film at this screening, fans were treated to a pair of mid-credits scenes, both of which are quite important overall to the plot, and also a ton of fun to watch. As they waited for the end of the credits, they also got treated to the Deadpool Rap from the soundtrack, so that alone made the wait worth it. Then the screen went black and there were no additional scenes.
Does this mean there is only that mid-credits scene for Deadpoool 2? Not necessarily. Anyone who attended those early screenings of Deadpool back in 2016 stayed through the credits and didn't see any scene. It wasn't until a week later, at the official release date, that the scene spoofing Ferris Bueller's Day Off appeared after the credits. There is a chance that there will be another scene tacked onto Deadpool 2 and we just don't know about it.
So it's probably best to stay through the credits just to be sure, even though you should do that anyway.