Tyrolean: Becka being rescued(click to enlarge)
There are many obscure tricks of rigging that are specific to the case of exploration, and are rarely used in UK-style SRT.
Read Sherry Mayo's SRT Guide - with diagrams!
A pendule is a technique for crossing a void more or less horizontally. It can only be rigged if you can get to both ends. The essential idea is to suspend a length of rope loosely across the pitch, anchored securely at both ends. To pass it, rig your descender on the rope and descend, as you would a normal pitch. Once the loop of rope below, going back up to the anchor at the far end, starts to become tight, attach your jammers to it and pull rope through until they take your weight; now prusik on this side, pausing to let out the rope through your descender as needed.
Read Sherry's notes and diagrams on Pendules.
There are a number of pendules left rigged in CUCC's caves, to avoid having to repeat death-defying climbs and traverses that were originally used to reach the far ends.
Practice above ground suggests that pendules work very badly unless the hole below is reasonably deep, probably at least half as deep as the length of the pendule; otherwise you end up prusiking against the force of the tension in the near-side rope to avoid hitting the deck, which is extremely hard work.
Tyrolean: Becka being rescued(click to enlarge)
A tyrolean is used in much the same places as a pendule - roughly horizontal traverses across voids - but is much more difficult to rig, and dangerous if not rigged right. The idea is to have a tensioned line across, which you can then run a pulley along.
The risk inherent in this is that of a t-hang, where the tension in the rope for even relatively light loads becomes enormous. To rig a tyrolean safely, really massive anchors are needed at each end - big naturals with backups, or multiple spits - with a completely independent backup line rigged parallel to the main line (but not under tension). A Z-rig or something similar can be used to tension the rope.
Read Sherry's notes and diagrams on Tyroleans.
Tyroleans are also important in rescue rigs, where they can be the only safe way to transport a stretcher across a traverse; this lies out of the scope of this guide, and is well covered in Life on a line; on Expo there should be a copy in the tatty hut.)
Rope protectors have now all but disappeared from sport caving in the UK, and I think it is fair to consider them an Expo-specific trick; I have never used a protector except in Austria.
A protector is essentially a sleeve of tough material that wraps around the rope with Velcro, and can then be clipped into place with a bulldog clip at the rub point. They are more or less self-explanatory to use - just remove the tector when you reach it and replace it once you've passed the rub point; I include them here because it is easy to forget that they exist. As a general principle, it's probably not a good idea to use them on trade routes, but they are ideal for the situation where you just want to descend a pitch quickly to find out if it goes or not (but don't forget to rerig later if it does go somewhere significant!)
If you don't have a tector handy, it's often possible to improvise using an empty tackle sack or dangly bag - you may need to hold it in place until your weight is across it on the rope, which should then keep it secure.