Where can i find each and every friendly monsters?

Tip: There are many free guides out there in the world wide web, why wait for a reply in the forums?

Anyway, The Mu will be found in the forest near Dali and the Observatory Mountain.

The Ghost is found in a forest near Treno (only in the dusk part).

The Ladybug is found in the forest which surrounds Black Mage Village.

The Yeti is found in forests around Madain Sari.

The Nymph is found in forests near the Iifa Tree.

Jabberwock is found in a forest east of Oelivert (this one is hard to find/get to).

The Feather Circle is found between Esto Gaza and the chocobo track in the Lost Continent.

The Garuda is found in the area above Gizamaluke's Grotto where you can encounter Grand Dragons.

And finally the Yan is found on Vile island south-west off the coast of the Outer Continent.

The first Five will want ores, and from then on the next ones will ask for more rarer gemstones obtained from the previous friendly monster. This sidequest helps you to attack against Ozma. And make sure you have stuff to be learned on your equips or you'll be wasting all that precious AP (from 10+).