There are 2 kinds of wormholes. Stable ones connect to a fixed exit point while unstable ones don't. The only way to know is to fly through one. If your ship exits the wormhole right next to another one you know it's stable but if the ship exits at a random location its an unstable one that just throws ships around the galaxy.

Jump portals

Some factions have ships that can create jump portals. These act as stable wormholes once both ends are constructed.

Space folds

Space folds can transport resources across vast distances. More details can be found here.

Plasma storms

Plasma storms hinder space travel. Ships can only travel with warp 5 through them. They appear at random at last a random amount of time. This can be configured at game creation.