Mostly to get the hang of how good MZ games can be.
RPG Maker has largely stayed the same across versions. So, unless you want to look inside the game and study & learn from it to copy what it’s doing into your own project in MZ… you can play games made in previous RPG Maker versions to get the idea.
Especially, since we can’t always tell for every RPG Maker game in which exact version it was made in. Like, Infinite Mana:
It’s either made in MV, or MZ. No surety on which one.
Also, you said not horror. But are we strictly staying with RPGs? There’s a car racing game I recently played, made in MZ, which was fun:
Or, an action-adventure game like Buffet Knight, which is also made in MZ (I believe)
It should be easy enough for first-time RPG players to clear without too much grinding and annoying stuff.
It should be beatable without any random encounters
These are not things you should worry about with RPG Maker games. If either grinding or random encounters are bothering you in a game you’re playing. You can upload the save file to saveeditonline and give yourself 999999 health & 999999 attack power & 999999 Gold to one shot everyone.
Here’s another example of an MZ-made RPG game you can play:
OPTIONAL: It should be made with either default graphics
This sort of contradicts you asking for ‘how good MZ games’ can be. Generally, good RPG Maker games either don’t use the default graphics, or use it little along with other graphics.