-Husband and wife in Umar Hills
You can ask them about a cottage in the area. You're looking for Valygar's, but they tell you about Merella's. See the weird strings.
-Original tougher Shade lord
He has an alternate, unused file. See sendark.cre.
-The Drow chest's guardians
Monsters that were supposed to guard the chest in City-of-Caverns, along with the beholder. See weird strings, and sahbeh02, 03 and 04.cre.
-Ulvaryl's dialog
See her dialog file.
-Drenden Shale taking care of Jaheira
After she was cursed by Ployer, that druid would take her with him. This was maybe cut because Jahs leaving the party could screw up the romance. Must have been found in the Druid grove. See drenden.cre and associated dlg file.
-Dog meat and vampire blood
Maybe substitutes for the crystal shard and Dace' hand. See weird strings, and the vampire stake item.
-Nilthiri's disease
Supposed to burst into deseased rats when she died (could be coded like the troll who spilts in two in Nalia's keep). See weird strings, drshnl01.bcs and sickrat.cre.
-Less hasty Gaelan Bayle
There's a string where you accept to follow him to his house after all (which you normally can't refuse). Might have to do with the alternate promenade cutscene.
-Choice of rewards for illithium quest
See weird strings.
-Amaunator statue's riddles
See weird strings.
-Falik coming to you for help
Asks you to go find his wounded friend Grancor (normally they're both at the same spot). See weird strings.
-Sahuagin ambush in the Sphere
Door supposed to lock behind you. See weird strings.
-Mook's vampirism
Might actually be Kachiko, one of the thieves who were supposed to help you against Bodhi in chap.6. Becomes a vampire, Arkanis Gath has a comment. See weird strings, c6kach.cre and c6kach02.cre.
-Yoshimo and the nymphs
See weird strings.
-Lady Diana and Lord Feveran
Who are they waiting for? Nothing proves that this is UB at all, I'd remove it from the list (along with a few more items).