Personal Geb

This build is mainly for my own reason, but anyone is free to use it, and modify it for themselves.

Early game is simple.
Guard Boots
Meditation(optional, my own preference)

I have noticed that Geb doesn't really need a Blink or anything like that because of his 1 Roll Out which with this build will get him to 754. No one seems to be able to catch him without slows or stuns (if the enemy team has a decent amount of slows/stuns then Blink will be good option to have). If you don't get Meditation, then you could start another item, or finish the boots.

Mid game isn't really a good term for this since you can buy the items before the middle of the match. But anyway here is where your defense will come into play.
Sovereignty
Bulwark of Hope
Mystical Mail
Stone of Gaia

These items can be bought out of order, for example if the enemy has 3 physical, start with Sovereignty, but if they have 3 magical, start with Bulwark.
I don't like to build 2 items of the same defense right after one another, this is why they are in the order they are in. If the enemy team has healing, replace Stone of Gaia with Pestilence.

Late game, also simple.
Reinforced Greaves
Gem of Isolation

Gem of Isolation is good for the slow, it can really help for team fights. You can also replace the Gem with Soul Reaver for more percent damage.

Physical Heavy
-Stone of Gaia
+Hide of the Nemean Lion

If the enemy team has more Physical Damage, replace Stone of Gaia (or Bulwark of Hope) and add a Hide of the Nemean Lion (or Mail of Renewal if you want health regen almost like Stone of Gaia did). However, unless the enemy team is all Physical, don't remove both the Stone and the Bulwark, you will need some Magic defense left.

Magical Heavy
-Mystical Mail
+Void Stone

This one is set to change because I have trouble building Magic Defense for some reason. Anyway replace Mystical Mail (or Sovereignty) with Void Stone (or Pestilence if the enemy team has a healer, and you haven't already bought it).

This build is not perfect, and it will get reworks when I find something that is better.

From what I have found playing Guardians (I own all but Sobek and Bacchus) they are very similar in build. I will be making guides for the others soon.