Enjoy the story first, that is the best part of this amazing game, and collect them all later if you want to. I would HIGHLY suggest not to hunt them all while playing through the game, it takes a long time and catching them will be easier later on in the games with items you get during the main campaign and the sidequests.
The spawns also different from grass spots, but even each individual spot, in case you have problems with finding a Nexomon with my guide, you can find a more detailed guide here, which is especially very useful for Palmaya beach: So if you see a Nexomon in my list and can't find it yourself, you might not be far enough with the main quest for it to appear there. Keep in mind that evolutions of Nexomon can appear later on in the story on spots where they weren't before. I hope this guide will be useful and that you'll find the Nexomon that you're missing. BTW the names I gave each field sucks, I know that, but I added a screenshot to each one to make it more clear which field I mean. Good luck, ill see if theres anywhere else I can find. I dont know if it actually affects something but maybe it helps. I'm pretty sure I'm still missing Nexomon, especially because while making the list there were more Nexomon added to fields I had already visited, but I listed all that I found. What I suggest doing is killing the creatures that arent the one youre looking for, since I tend to get the same nexomon/something similar if I dont. I've been running around a bit more than I needed to be, just to fill up this guide as much as possible. This guide will list the Nexomons I found in each field. There should be an entrance to the vault. Keep moving forward and use the wind power to get to the other side. Go inside, follow the route, climb up the stairs, make a left, and go up instead of leaving through the left exit. If your using the location link that was stickies somewhere here I’m sure your in right spot. At the bottom-left corner, there should be a cave. Its in that building north of Drake Isles, gotta progress story to get in there behind the sleeping dragon. I just ran into Phantra, its 3rd evolution. Searching the screen above the trap crafter on Palmer a. Finally ran into one, it was in the grass just below the island with 4 bridges coming off it (on the drake isles) Flash 3 years ago 8. Others I have no clue where to find them. Been searching for about 2 hours now, no waser. The developer is tweaking the distribution rate daily, so this should get a lot better over time. These lists take a really long time to make.) I’ve kept all of the Nexomon in a single post so you can quickly hit CTRL F to do an easy search for any Nexomon you might specifically be looking for. (Perhaps I’ll eventually do a mobile list, but I don’t know. A few a know where they are but they just don't show up for me. This list is specifically dedicated to Nexomon: Extinction.