Freezeland - Digimon World 1
Freezeland is another one of the midgame locations that you can recruit a lot of Digimon from. You will likely be returning to this location many times throughout the game since not all Digimon here can be recruited right away. One of those Digimon is named Mojyamon, to recruit him you will need to trade all 3 that you find for items.
There is actually a 'bug' with this Digimon where you can make infinite Bits by repeatedly trading for the same items over and over. In order to do this though you need to recruit the correct Mojyamon to your city and leave the one you want here - more information is on that below.
Last but not least, Angemon is the other Digimon you'll have to go out of your way a bit to recruit here. You'll find him inside of the Ice Palace which requires a Vaccine type Digimon to enter.
Mojyamon
Requirement: N/A
There will be a total of 3 Mojyamon which you can find on the ice flows in the most south-eastern portion of Freezeland. When you speak with these yeti they will offer to trade you an item in exchange for another one. You will need to trade with all of the Mojyamon, the final one will join you once you trade the last item to him.
Important: We want to keep the Mojyamon in the southwest corner since he offers the best trades. That means you'll want to do this Mojyamon first or second, but not last.
Southwestern Mojyamon Trades
Omnipotent
Med. Recovery
DigiAnchovy
Southern Mojyamon Trades
Giant Meat
Speed Disk
Black Trout
Southeastern Mojyamon Trades
Happy Mushroom
Digi Mushroom
Super Carrot
Penguinmon
Requirement: N/A
Penguinmon is found to the east of the ice flows in a little igloo. Your first time talking to him he'll be standing outside the igloo waiting for you, making him easier to find. In order to recruit Penguinmon to the city you will need to beat him in a curling match. This is pretty easy to do if I am being honest, if you lose the next time you challenge Penguinmon you'll need to bring him a fish. Basically, you get one free attempt and after that you have to pay a fish to challenge him.
Whamon + Ogremon (Encounter #3)
Requirement: Defeat Ogremon in the Ogre Fortress
After you beat Ogremon in the Ogre Fortress you'll be able to find Whamon in Freezeland; he'll take you to his secret cave which is where you'll have the third Ogremon fight. The Ogremon fight and recruitment of Whamon is tied together, so you'll have to beat Ogremon to proceed.
Once you beat Ogremon at this location speak with Whamon again and he will join your city. You can use Whamon in the city to travel back to the secret cave and get some items as well as use him to travel to a whole new area of the game called Factorial Town.
Fighting Ogremon this time can be a challenge because he comes with an Ultimate Digimon called WaruSeadramon. I recommend you bring a lot of items for your Digimon and/or have a powerful AoE attack that you can spam at the start of the battle to take out the adds first.
Ogremon Locations:
1. Great Canyon, run towards the elevator and he will ambush you
2. Great Canyon, take elevator or ledge down to canyon floor and scare the Agumon you see down here and then follow him inside
3. Freezeland, talk with Whamon to travel to his cave, you'll find Ogremon here
4. Drill Tunnel, Ogremon will take control of the Drill Tunnel. Enter and beat him the final time to make him join you.
Frigimon
Requirement: Any Digimon that is vulnerable to the cold. This includes any Baby/In-Training Digimon as well as Agumon, Kunemon, Greymon, Meramon, Monochromon, Centarumon, Tyrannomon, Kuwagamon and Kabuterimon
Recruiting Frigimon comes in two parts, for the first part you need to bring a Digimon that is vulnerable to ice into Freezeland and stay here long enough to get Sick. The easiest way to make your Digimon sick is by feeding it Moldy Meat or some other food that will make it sick. Once your Digimon is sick walk around a few more steps and you will collapse and be taken to Frigimon's igloo.
The other way to do this without any Moldy Meat is to avoid sleeping and feeding your Digimon until it gets sick. After visiting Frigimon's igloo for the first time you will be able to return whenever you want. Come back with another Digimon who is not vulnerable to the cold and talk to Frigimon again, this will make him join your city.
Garurumon
Requirement: N/A
South of the igloo with Frigimon you'll find Garurumon. You'll need to beat him twice, the first time you beat him he'll ask you to return the following day between 4 - 8pm. Two things to mention about this, Garurumon will have less health if you return on the day immediately following your first fight. Also, during the second fight you will not be able to use any items or instruct your Digimon at all.
Once you beat him the second time he will join your city.
Angemon
Requirement: A Vaccine Digimon
To unlock Angemon we'll need to complete the Ice Palace dungeon in Freezeland. You will need a Vaccine type Digimon to enter the Ice Palace and I recommend it be a strong one since there will be a lot of combat. Once inside run around near the life-like statue to trigger some dialogue. When you try to leave your Digimon will discover a hidden passage, go down into the new area and search the wall on the immediate right hand-side for another secret passage.
From here things get a bit confusing since there are multiple teleporters in each room and you need to choose the correct one to advance. The first teleporter is directly east from where you entered and the second is in the top right of the four way room. If you'd prefer to watch a video of me running through this dungeon check out my How To Get Angemon In Ice Palace Video.