You can just do Console Commands on PC to get followers, but this way is legit, so it's good for console users.

I've got back into playing Oblivion (Loving it) and I decided to make myself a rather large group. In game size terms and such you may consider it a small army. Most of you probably already know how to do this, but meh, maybe one or two don't, so I shall show you.

1. Familiars. Simply summon any creature.

2. Atronachs (Mage's Tower DLC): Use frost/fire/void salts to summon a permanent atronach to follow you around. I prefer Frost, because they're relatively quick and powerful, while flame is faster yet weak and the super tough storm atronach is by far the slowest.

3. Man-At-Arms (Battlehorn Castle DLC): Simply kill off the bandits and have one of these follow you.

4. Fighters Guild: I think you may have to be Guildmaster, but you can have a Fighter follow you.

5. Mages Guild: Finish the quest and become Arch-Mage. Then you can have Mages follow you (Obviously use a stronger mage, in the BLUE robes)

6. Dark Brotherhood: Finish the quests and you can have a murderer follow you. This one's good because some of them can go invisible, go stealthy and all sorts.

7. Knight of The Nine (KotN DLC): Find the Knights' HQ and do a few of the quests so more of them show up to fight for you and have one of them follow you.

8. Thieves Guild: Finish the quests and you can have a thief follow you.

9. Crimson Scar (Evil Grotto DLC): Buy all of the stuff for this add-on, and you can have a Crimson Scar follow you around. They're similar to the Dark Brotherhood.

10. Adoring Fan (Yes I'm serious): Finish the Arena and the Adoring Fan will follow you around. Send him into the battle first. Please.

11. Shivering Isles: You get the Lesser Power later on in the Shivering Isles main questline and you can summon either a Dark Seducer Guard or a Golden Saint Guard. These can be summoned along with a regular summoned follower.

Now, to test your army!

Go to Fort Sutch when you're at the point in the Main Quests where Oblivion Gates open up everywhere. If you've done the Dark Brotherhood, you should be familiar with this location (It's North of Anvil, I think. It's where you kill Rodric) There you will find a couple of Imperial Soldiers who ask for your help in repelling an attack from an Oblivion Gate close by. When you say yes, will your followes in tow, you will be faced with a rather powerful horde of Daedra. When I went on my own, I died.

Good luck!

Erm... I was in the Oblivion Spoiler section... Why is this here...? Mods move please?