Venus Djinn, Before Lemuria
"Echo" joins automatically when you leave Daila Village. "Iron" can be encountered randomly in the forest just west of Madra. In Gobomba Statue, reverse the gears inside and find the level you met the mouse, and then jump down the left-most pink gear to find "Steel." In the chamber of the Black Orb, go down the ladder and use "Cyclone" to expose the entrance to "Mud's" cave. "Flower" is in Taopo Swamp near the bridge. Move the pillar in front of the holes billowing steam, and then jump down to retrieve it. Finally, "Meld" is located in Islet Cave, after you've completed the fetchquest for the animals.
Venus Djinn, After Lemuria
"Petra" is randomly encountered on the world map; follow the trail northwest from Shaman Village Cave, then take the south branch. "Salt" waits in a large patch of grass in Contigo Village; use "Scoop" on the bare patch of ground to find it. "Geode" is in Atteka Inlet right after Isaac joins you; use "Lift" on the nearby boulder and expose him with "Cyclone." "Mold" is located in Prox Village; after bumping into it, dig it out of the snow with "Scoop." "Crystal" is in Yampi Desert Cave; you'll need Teleport to reach it.
Mars Djinn, Before Lemuria
"Cannon" is located on Dehkan Plain, but cannot be approached directly: chase it and drop down the hole it jumps into from above to take away its Pound Cube, and then use Pound to block the path and chase him down. You can get "Char" by trading Healing Fungus from the Gondowan Cliffs in Madra. "Kindle" lives at the top of the Gondowan Cliffs. "Spark" lives underground in Mikasalla Village; use "Scoop" near the sheep there to enter his cave. Trade the Dancing Idol found at the end of Gaia's Rock to the girl in the pink-roofed hut Izumo to obtain "Coal". Finally, "Reflux" is on the 4th floor of Tundaria Tower.
Mars Djinn, After Lemuria
"Core" is a random encounter on the world map, southwest of Jupiter tower. "Tinder" is in plain sight in Hesperia Settlement; reach it by pushing the tall box on the cliff down, and then using "Move" to make a path to the Djinn. You need "Force" to find "Shine;" use it on the stump behind the inn in Contigo Village. "Fury" is on the second floor of Magma Rock. Finally, after revitalizing the Mars Lighthouse, break the ice at the entrance, enter the right-most door, and climb the stairs to find "Fugue."
Jupiter, Before Lemuria
In the Shrine of the Sea God, find "Breath" and block its escape path with a pillar. Blitz is in the third region of Yampi Desert, on a tall cliff; jump across the pegs to reach it. The village elder in Garoh village will give you "Ether" after you talk to him after you've used "Reveal" to expose his true form. "Waft" is located in the Kibombo Mountains; you will need to use "Frost" on a pillar and "Grow" on a sprout to reach it. "Haze" is on Apojii Island; use "Sand" to burrow to the east side of the island, and then slide down the waterfall and enter the cave there. "Wheeze" is on the world map, southwest of Tundaria Tower.
Jupiter, After Lemuria
"Aroma" is in Shaman Village, which you can reach with "Lash." "Whorl" is in the Jupiter Lighthouse; use "Hover" to reach it. "Gasp" is at the end of Shaman Village's Trial road; use "Hover" at the purple sigil and "Lift" a rock out of the way. Then use "Reveal" at the end. "Lull" is found in Loho Village, after blasting the wall with the cannon. "Gale" is on Treasure Island, near Izumo.
Mercury Djinn, Before Lemuria
"Fog" lives in the Kandorean Temple; take the left fork from the entrance to Dailia and use "Lash" inside the cave there to reach it. "Sour" can be encountered on the world map in a triangular forest northeast of Mikasalla Village, south of Osenia Cavern. "Chill" is on the world map, southwest of Naribwe Village, south of the bridge. "Spring" and "Shade" are equipped on Piers when he joins. "Steam" is at Aqua Rock; you must use "Parch" on the green head spewing water to reveal the path.
Mercury Djinn, After Lemuria
In the Lemuria waterway, use "Grind" to pass the brown rock to the left of the entrance to Lemuria City, and then use "Cyclone" on the pile of leaves and "Tremor" on the statue to obtain "Rime." "Gel" is on Kalt Island, northwest of Loho Village. "Eddy" is in the Shaman Village Cave, only accessible after Isaac joins the party. "Balm" is in the Mars Lighthouse behind the ice puzzle. Finally, "Serac" is in Islet Cave; use "Teleport" to reach it.