Say I DM a Storm King's Thunder session for Adventurers League. In this hardcover, there are multiple instances of having to randomly distribute magic items. The instructions are as follow:
Sometimes a treasure hoard contains one or more magic items determined by rolling on the magic item treasure tables in chapter 7 of the Dungeon Master's Guide. When determining a random magic item, roll a d100 (or have a player roll for you) and consult the specified table in the Dungeon Master's Guide. If your players have a "wish list" of magic items, or you think a particular item might be useful to the party, you can forgo the roll and select an item from the table.
Now what would happen if I were to roll a 10 on Table F, which says Weapon +1? It can be any type of weapon, but there are no tables for randomly choosing the type. Is it okay to choose a type that would be useful to one of the player at the table? Maybe ask everyone for their prefered type and roll between those?