Spent about 2 hours last night grinding my characters from level 40 > 50.
I was doing this in the 2nd land. There are 3 Dream Eater, 1 Dinogator and 1 Omnihunter FOE on that map. I would enter/exit the map, checking to see if they were shiny. Hopefully, I got lucky and also found food that would increase the EXP.
1 defeated shiny Dream Eater, with the EXP boost skill (holy gift) and the food that increases EXP, gave me 50k EXP.
1 defeated shiny Dinogator (these take a few days to respawn after killing btw), with holy gift and the food EXP, gave me 73k EXP.
So if you want to do some grinding, I think this is a good spot.
I thought about retiring my team and grinding once again but I may just wait till 99 to do so.
Time to tackle the 4th land. Good luck to those in the 3rd labyrinth. So annoying.