One of the most boring things I have found in the wild and wooly world of AD&D is the low level of creativity in random encounters.
I live for non attacking random encounters that still present some kind of problem or issue for the PC's.
In fact, I love to mix things up like this so much that I do not have a regular old "Random Monster" check. I have a table that sends the DM to a set of sub-tables for a variety of encounters most or all having some kind of impact on the PC's, just not always violent.
For example, my Random Encounter table might include my "Who's Who" sub-table that looks to sub-tables indicating encounters with NPC's engaged in activities, talking to the PC's, giving/handing/slipping them something that will affect them later or maybe just at the moment.
some of my most infamous sub-tables include Tolkien characters randomly being seen or approaching the PC's looking or asking for something.
Dwarves and other types that have something to do with one another, that kind of thing.
Another favorite sub-table that is checked is the "Stuff happens" table which, depending on the PC location or environment (urban, suburban, rural) might lead to a wagon/cart wheel falling off. A horse throwing a shoe, traffic being re-directed, animals or children running out in front of you, thieves or hitchhikers/stowaways getting or being found out.
These are things which add new dimensions to the role-playing and events of the game.
Any game can add 20 orcs or 40 goblins or 10 bugbears, etc...But it's a hoot to have PC's discover that hitchhiking dwarf they dropped off at the last town somehow managed to swipe someones money or magic artifact or even money they needed to pay for something later in the game.
Didn't see that coming, did they? HA HA HA HA.