In FF8 there are 22 Guardian Forces (and quasi-GFs) you should get.
QUETZALCOTL:From Squalls computer in the classroom at the beginning of the game.
SHIVA: From Squalls computer in the classroom at the beginning of the game
IFRIT: Defeat him in the Fire Cavern outside Balamb Garden as part of the test
SIREN: Draw from the boss at the top of Dollet Satelite during the Exam
BROTHERS: Defeat them in The "Tomb of the Unkown King" outside Deling.
DIABLOS: Summon him using the Magic Lamp given to you by Cid after completing your Exam. After Summoning him you must defeat him. He is VERY difficult. Save before you fight him.
CARBUNCLE: Draw from Gargoyle/Lizard bosses in Deling during Parade.
LEVIATHAN: Draw from NORG in Balamb Garden. Make sure you draw from NORG and not the pods.
PANDEMONA: Draw from Fuujiin in Balamb Town.
CERBERUS: Fight and Defeat him in Galbadia Garden.
ALEXANDER: Draw from Edea at the end of Disc 2.
DOOMTRAIN: Get Item "Solomons Ring" from Tears Point before Lunatic Pandora is summoned. (A good time to get this Item is right before when you are supposed to meet Dr. Odine at the Launch Pad). Once getting this item "Mug" Marlboros outside the Sorceress Shrine until you have 6 Marlboro Tentacles (Marlboros are also at the Island Closest to Heaven) Then buy 60 Remedies and use Alexanders "Med Lev Up" Skill to make 6 Remedy+'s. Next you need 6 Iron Pipes. These can be "Mug"ed from the Yellow/Green Monkey enemy outside Deling. If you don't have these and you can't get back to Deling you may have to wait until after you have the Ragnarok to get them. After getting all the Items (6x Remedy+'s, 6x Iron Pipes, 6x Marlboro Tentacles and 1x Solomon Ring) use the Solomon Ring from the Item Menu and you will receive DOOMTRAIN.
BAHAMUT: Defeat him at the Galbadia Underground Research Facility. It is located in the South-West corner of the map. It is in the middle of the Ocean. To fight him you must talk to machine (Walk when the light is off) then pick the first answer for the first question, second answer for the second and the third answer (It's hidden) for the third question. You will then fight Bahamut.
CACTUAR: Fly to Cactuar Island in the South-East section of the world and run into the giant Cactus that you see going up and down. You must then defeat Giant Cactuar.
TONBERRY: Go to the Centra Ruins (After recieving Odin, see below) and fight 20 Tonberries. After defeating the 20th (or so) the King Tonberry will come. Defeat him and Tonberry will join your team.
EDEN: Draw from Ultima Weapon in Galbadia Underground research Facility. To get to Ultima you must defeat Bahamut first (see above)
The following GFs are non-drawable. You must either use Items to call them (Pheonix and Chochobo) Or they appear randomly (Odin and Gilgamesh). I'm not sure how Mumba and MiniMog are used since I don't have a pocketstation.But I believe that you use items to call them as well
CHOCOBO: Catch and name a Chocobo then use Item Gysahl Greens during Battle.
PHOENIX: Use Item Phoenix Pinion during battle.
ODIN: Defeat him in Centra Ruins. Appears randomly at the beginning of battles.
GILGAMESH: Receive Odin before the end of Disc 3 and Seifer will kill him. Gilgamesh then show up to replace him.
MINIMOG: (POCKETSTATION NEEDED) Receive Minimog during "Chocobo Adventure" PocketStation Minigame.
MUMBA: (POCKETSTATION NEEDED) Defeat "Chocobo Adventure" PocketStation Minigame
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