What have been your favorite glitches you’ve found/read about/watched in the Halo games?
Personally, I learned this one trick for Assault on the Control Room from a guy in a YouTube comment section of a Generalkidd video; (For those who don’t feel like reading a lot, ignore)
Honestly, off the top of my head, the only glitch I can think of is the Halo 2 super bounce. I am sure there are loads more but that is the only one I can recall as of now. It is really fun to just bounce really high and get into unreachable places.
someone beat me to it, Super bouncing on Halo 2. I also really enjoyed being able to, as we used to call it back in the Halo 2 online days "getting out of the map". Another Halo 2 glitch was the double shot, quad shot and bxr tricks that I dont believe were intended.
In CE(must be on co-op), pillar of autumn, there is a way to jump back into the cryotube and get launched into the ceiling. If you are VERY careful you can navigate all the way to outside the ship by jumping on top of lights/objects that are solid from the top of inside the ceiling. It is extremely challenging and like a little jumping minigame, akin to those super hard jump challenge custom maps in Halo 3. Very cool, but frustrating if you're trying to get outside.
By far and away the trick in H2 to get you infinite sword ammo in 2-part levels (eg., Arbiter and Oracle). I discovered it accidentally as a kid and was super thrilled! I later learned it was something a lot of people used to make it easier to get through levels. It was one of the first things I tried in MCC when I first played it, but sadly the trick does not always work in MCC.
I like the one where you can duplicate mongooses in the mission The Pillar of Autumn from Reach.
Honestly the most entertaining glitch I've seen is the simple one that the HLG team Mi-Seng pulled off during the Asia HCS Qualifiers in 2016. The fact that they did it on the livestream in front of hundreds of viewers made it even more hilarious, but at the same time it was an effective wake up call for HCS when it comes to fixing map glitches.
Don't think I have a particular favorite glitch. I just love out of bounds glitches in general. With that said, I think my favorite non-glitches that people might mistake for glitches are vehicle launches. It's just such a clever combination of game physics that gets you into some cool places.

The AotCR skip skip doesn't actually require co-op, nor does it require clearing the enemies. You can just go immediately left when you come to the bridge, drop onto the ledge, drop to the lower ledge, and then to the bottom. There is no kill barrier. The game just kills you if you spend too long in free fall. This skip is actually a standard speedrun trick.
Halo 2, rocket-sword glitch! That was a pivotal glitch to explore outside the map and really explore for other bugs, glitches, and Easter Eggs.