All the glitches (not easter eggs; also, the hologram "glitch" is not a glitch, it's an easter egg) I know:
In Forge, if you start shooting in with a Spartan Laser, and go in to Forge Ball, there will be a light.
In Forge, if you shoot someone with a Plasma Launcher and they go into Forge Ball, it won't explode until they come back out of Forge Ball. Same thing with Plasma Grenades.
In Forge, if you make a triangle out of shields in Spire and shoot plasma into it, it will continually ricochet until the plasma ammo eventually floats in mid-air. This glitch works with these weapons: Fuel Rod Gun, Plasma Launcher, Spiker, Plasma Repeater, Plasma Pistol.
In Forge, if you put an Armor Lock down and start using it, go into Forge Ball, spawn another Armor Lock and 'Delete All of These', you will have Armor Lock around your armor the whole time, unless you go into a kill ball, fall off the map, or get assassinated.
In Forge, if you go, with your Forge Ball, up to the map boundary in the sky, look up, and spawn a teleporter, you will be able to push it outside the boundaries.
If you know how to get outside the map in Spire, there is a Pelican (the one for use in Invasion).
Well, this is not a glitch, but there are several random doors and cigarettes if you go into Theater in the Long Night of Solace space mission.
There are multiple ways to get out of makes such as Boardwalk, Reflection, Forge World, Spire, and Sword Base.
If you are in the "no-weapons glitch", there is a glitch that no one really knows about. Because it is hard to do. When you have no weapons, if you do this all in one motion, your Spartan will be stuck in an animation that you can walk around in; your legs and feet will be moving around in circles and your Spartan will appear to be looking down, this also glitches your camera; for example you may be looking forward which could be behind your Spartan--this will allow your friends to be able to assassinate you from what is the front of your Spartan, but behind where your "camera" is facing. So do this all in one motion with no weapons (you need to have toggle crouch): toggle crouch, spin to the left, stand up, spin all the way to the right and toggle crouch again. You have to spin and crouch all in one motion.
There are several more glitches I don't feel like explaining.