The unofficial FRUA v1.3 patch is a backwards compatible "bugfix" which (when it's upgraded to semi-official, I suppose) can be applied to a "default" installation to do the following:
* Copy protection bypass
* Death by old age bugfix
* Dungeon 36 do-only-once bugfix
* River combat enabled
* Thief Saving throws corrected
* Various minor incorrect saving throws (comparing the saves to the 1st edition DMG) fixed
* No animated pictures in text event bugfix
* Treasure Pic 2 display bugfix
* Temple healing for PCs with high CON scores bugfix
In my testing (so far), it can usually be added (pasted into) an existing diff.tbl with no problem, but there are probably some serious exceptions, such as Oriental Adventure modules, and any others where program events have been added or changed. (i.e. the Special Item event changed to the Special Ability event.)
In any case, if the author didn't design for it, it probably won't make a huge difference.
CPIC.TLB is a revised library of monster combat icons based on results of the UA community's Survivor competition for combat icons.
MONST.GLB Update v1.0 is Darius Whiteheart's revised monster library. Among other changes, it appears to use the 2e monster thac0, so low-levels are a bit easier than 1e, and high levels a bit tougher. Most monsters subject to Charm Person have been corrected.
I think these are neat adds, but they're not really necessary to play the game.
I know of no file called TO.rar, but check out the pix to see if they're any good!
(Show.exe from Dan Autery's TLB Utilities will display the TLB files, but you may have to run it through DOSBox if you're using Vista.)