Dragon: Get a monster to Class "B" no higher and you will get invited to an invitational on August 2nd Week. The prize is a Dragon Tusk. Use the Tusk to combine any 2 monsters.
Centaur: Get a monster Class "B" or higher and go on the Mandy Desert Errantry. Your monster might return with a Spear and right afterwards a Centaur will attack. You have to fight the Centaur but you don't have to win to keep the Spear. Use the Spear for combining any 2 monsters.
Wracky: Get a monster with Fame of 90+. Win one of the Major 4 "S" tournaments and a fan will send you a doll. The next week or so (not sure) the doll will disappear. Next time a monster dies, the doll will reappear as a wracky.
Durahan: Get a Class "A" monster to go on the ParePare Expedition (Oct.1st week). Find the Old Sheath. After you come back go to the Item shop and the woman will tell of a sword being recovered. Get invited to Invitational Feb. 4th week. Prize is a Double-Edged Sword. Use the sword to combine any 2 monsters.
Zilla: Get a Class "B" or higher monster to go on Torble Sea Errantry and you have to have your stable upgraded at least twice. You are told of a creature running around. Complete all 4 parts of the errantry and you might be able to fight the Zilla King. Beat the Zilla King and your monster will come back with the item Zilla Beard. Use the Zilla Beard for combining any 2 monsters.
Bajarl: After building your stable and house the final time (May 4th week). You stay behind and watch them build. The builder will give you a pot to keep his he builds a secret. Use the Pot for combining any 2 monsters.
Phoenix: Go to Kawrea Expedition (not sure if you must go more than once). You might find an item called Fire Feather. Use the Feather for combining any 2 monsters.
Joker: Get a monster Class "S" and go to Kawrea Expedition. Find the Mask and use the Mask for combining any 2 monsters.
Undine & Niton: Get a Hopper Class "B" or higher. It will eventually dig up some hotsprings and a slate will appear. Use the Slate for combining any 2 monsters to get the Undine and you will also now be able to get Niton's from your cd's.
Ducken: You must get the Duck parts from getting 5 diamonds from Cup Jellies and then find the Strong Glue in the Torles Mountains Expedition and then get another doll. The Glue will only assemble the second one. Use the second doll for combining.
Beaclon: Get a worm (any type I think) and feed it at least 30 Cup Jellies, have your worm live up to 4yrs, have loyalty at 80+, and don't get keep it's class at "C" or lower. On June 4th Week it will spin itself into a cocoon. It will hatch into a Beaclon with same stats/age/name, but the attacks will be different.
Jill: Find item Big FootPrint on Torles Mountain Expediton. Have a monster Class "B" or higher and go on the Speed Errantry. You are told of a strange monster running around. If complete all 4 parts of the errantry you might run into BigHand. Beat BigHand and your monster will return with Item BigBoots. Use Boots for combining any 2 monsters.
Metalner: As the trainer you must be Rank 8 or higher (must have beaten at least 2 of the Major 4 "S" tournaments) and you must have a monster on your ranch that is class "B" or higher (<-- not sure but that's what I was told :) ) September 1st week if the weather is good (not raining) a UFO will appear. You will then see the UFO 3 more times if the weather is good (don't worry if it rains.. it will just appear the week after that). An Alien will give you a crystal. Take the Crystal to the Shrine in Town. Now you can get Metalners from your cd's!!
Mock: Somewhere in the game, I don't know when, go to the item shop, Coltias auntie should give you some seeds for free, then, on the week after ya get them Coltia should plant them, then, after around 3 to 6 years it should grow, bloom, and then die, then Coltia will ask you if ya wanna water it, do so, then after your next monster dies, it should become a Mock.
Ghost: Let a monster die and have a funeral for it. After some time Master Pabs will come along and yell at Colt for not keeping the altar clean. After that happens she will ask if you want to upgrade the alter. Do so. Every year on 3rd week of March you can upgrade the shrine. Once it's upgraded for the 3rd time Colt will find a stick. Use the stick while combining to get a ghost.
Credits: Great thanks to Colton Bole for the How to get a Mock info.
Everyone! Give a round of applause to Marcober for the How to get a Ghost info!
Great great thanks to Hokey for revising Zilla, Ducken and Ghost! Everyone repeat after me! "Thank You Hokey!"