The Adventure of the Silk Jerkin fits somewhere in the early career of a Planescape PC.

I have described a number of magical items that are often made in the form of bags, an alternative set of abilities for intelligent swords, some brief notes to integrate the halfling subraces of 1st Edition into the modern game, random tables for growth of settlements and procedures for characters to lose or voluntarily give up class levels.

The flesh shape spell might interest arcane casters.

Dire boars might appeal as mounts or combat beasts.