Beyond Stunfisk, the monkeys and Victini, the data pack adds two more families: the Tympole evolution line and the spooky Gastly family. The pack gives less specific spawn guidance for these two, so it helps to search broadly.
Finding the Tympole Line
Tympole is meant for wet and watery areas. To find it:
1. Search near water of every kind, such as rivers, lakes, shorelines and wetlands.
2. Swamps are a good place to start, since they are wet. You can also look for Stunfisk there at the same time.
3. Walk slowly along the water's edge and check the shallows. Small water creatures are easy to miss from a distance.
4. Once you catch a Tympole, keep training it with your team to work toward the rest of its evolution line.
Finding the Gastly Family
The Gastly family is a ghost-type line. The pack does not list a specific biome for it, so try this:
1. Explore a wide variety of biomes, and visit each one at different times of day.
2. Keep an eye out for floating, moving shapes. Every creature in this pack has custom animations, so a ghost drifting around you will stand out.
3. Keep notes on where you spot one. Once you know where it appears, you can return there to find more.
Tip: Explore new chunks rather than circling old ground. Fresh areas give you better chances at encountering creatures you have not seen yet.