25 of the glitches and bugs I found in my playthrough:

[Maplenose]

1. You can build to the edge of the world, and use fly there, and it will give you the prompt twice.
2. You can use Dig indoors, which is irreversible and can potentially create an infinitely tall building for some pokemons' happiness. (don't ask how I know lol)
3. You can use Attack on pokemon eggs, which, if they are shiny, will display the shiny animation. I've also found that they hatch into shinies 100% of the time, and non-shiny pokemon eggs never hatch into shinies.
4. You can see the gender, type, moves, level, and shininess of a pokemon before it hatches. (unintentional?)
5. Randomly when changing biomes, the music will die until you reload the game, or fulfill some unseen requirement.
6. Random EVO stones include the Sweet Apple, which, from everything I know, isn't usable in game. (could be usable, idk)
7. You can run through pokemon when they move against you, if you time it perfectly.
8. In-game time passes when in battle. (unintentional?)
9. If you surf with Raichu, their sprite will change to the surfing pikachu sprite until you reload the game. (excluding battles and menu)
10. You can read naturally generated signs from behind, while you can't read player placed sprites from behind. (inconsistent, and kinda weird)
11. You can infinitely generate Ashen Soil by combining water and lava. (Unsure if a feature or a bug)
12. If you run into something and keep holding the movement button, you'll be stuck in the same tile even after the thing you ran into moves out of the way.
13. You can avoid the sharp attack boost of angry pokemon by attacking first, even if they are already chasing you. (Unsure if a feature or a bug)
14. You can kill wild pokemons' eggs by attacking them and using moves without making the parent angry.
15. The music for the Unown event cancels out when you move to a new area.
16. The map sprite for water constantly changes when you come near it. (Just annoying to look at)
17. There is no way to farm encounters involving the move Smash, as rocks can't be restored without Dev mode.
18. Running backwards or using dig without fly while at the edge of the world will cause visual bugs.
19. Pokemon can breed indoors. (I tried to tell you lol)
20. The area that your map fills in when traveling is inconsistent, sometimes shrinking and growing randomly.
21. You can't get Apricorns from big trees. (Inconsistent)
22. Unowns don't have movement animations, and thus, you can't tell when they are holding something. (Unsure if a feature or a bug.)
23. Softlocking yourself is very easy, like... too many ways to put on this issue type easy. Please fix a couple, at least.
24. The mansion. Can generate. On. The. Volcano. It is... so ridiculous even looking at it on the map. (Unsure if a feature or a bug.)
25. Pojkemon don't even have to be the parents of the stolen egg to get mad when you steal it. More to be added later on as I discover them.

[PigmyRhino]

I've encountered a lot of these too.

8 is important to me because I think time should stop when in battles. Also, my current map has the mansion on the volcano, so that's fun lol

[Morearmsthanlegs]

How do you combine water and lava?

[Maplenose]

How do you combine water and lava?

To combine water and lava, use the dig field move to create lines between the two, eventually connecting to make Ashen Soil

[Invert72]

3 isnt a glitch, it's an intended feature used to hunt for shinies