Angryverse/Fan fictions

Fan fiction (or fanfic) is fictional writing written in an amateur capacity by fans, unauthorized by, but based on an existing work of fiction. The author uses copyrighted characters, settings, or other intellectual properties from the original creator as a basis for their writing.

Alternate Universe
A way for fans of any franchise to basically do a "What If?" situation that many fans to put into a timeline that isn't canon to the normal timeline for the Angry Birds franchise. It's also referred to a Headcanon. For example, most of the stuff that fellow fan Marisela Payers comes up with are mainly part of the many Alternate Universes, due to the amount of ships and headcanons she comes up with.

Crossovers
Crossovers isn't something new for a franchise, in fact Angry Birds has done a lot of crossovers including Sonic, Transformers, Rio, Star Wars. However, most fans like to make Angry Birds crossover stuff that would either work or is just impossible due to the licensing of the franchise. There is an upcoming Tiffany Fisher production titled Scooby-Doo! Curse of Daphne's W.A.P., in where it will be a crossover with the Scooby-Doo! franchise, but Rovio wouldn't most likely do it officially due to not being a part of the Warner Bros' brand.

Sometimes that isn't the case as they can sneak in characters from another franchise, but treat it as a promotion. Donald Duck is a good example of this, as a Disney/Angry Birds crossover isn't going to happen anytime soon, but he was included as a promotion in Angry Birds 2 for the DuckTales 2017 reboot on Disney XD.

Self-Insert
See: Tiffany Fisher

Alternate Universe
A way for fans of any franchise to basically do a "What If?" situation that many fans to put into a timeline that isn't canon to the normal timeline for the Angry Birds franchise. It's also referred to a Headcanon. For example, most of the stuff that fellow fan Marisela Payers comes up with are mainly part of the many Alternate Universes, due to the amount of ships and headcanons she comes up with.

Fan games
Fan games and mods isn't something new for a franchise, in fact, many franchises such as the Sonic series had fan games in the past and Sega allowed them to stay playable. One example of a fan game is Angry Birds Power Trouble.

Other few examples are listed here:
 * Angry Birds Maker - A similar game to Super Mario Maker
 * Angry Birds Multiverse Madness - A game crossing over the Classic birds with other versions of the birds from other universes such as the Movie birds and the Space birds as well the pigs…
 * Angry Birds Seasons Mod Remake - A mod for Angry Birds Seasons which focuses on adding cheats, birds, episodes, and items