I had a dungeon with a statue that produced minor negative effects on characters. I needed a chart. So, I basically revised the chart from the 1e DMG's artifact and relics section (which I think is one of the most beautiful innovations in that book).
I figured minor effects might be minor because they're mostly cosmetic, or they might be more serious but limited in duration. One thing that happened during play, was I'd made cards for effects that weren't obvious to observers and players had great fun roleplaying out the effects. So, one good guideline for any of these magical effects is to think of those that players might be able to, and be interested in acting out.
Because I had these cards, I needed a way to keep track of them (I wasted a lot of time at the table shuffling through them). The first thing that came to mind was to mark them with playing card suits. I thought Clubs might fit minor malevolent effects. Then I thought, why not finish out the other categories of effects? I could have major malevolent (Spades), minor benign (Diamonds) and major benign (Hearts). Heck, with all the suits, I could even have the option of players drawing cards to randomize.
So, I started working up my chart to share with you all. My original chart was just 20 effects. But I thought, for those of you that have d30s it would be cool to have that many options. So, my chart is now 1-30. But I was careful not to arrange it by power like a Stepped Chart. I tried to make sure each 10 result range had a mix of effects that are permanent, cosmetic, and affecting personality.
What I realized is, once you combine that feature-- a chart with vertical flexibility-- which allows you to use 10, 20 or 30 results, and thematic charts that are simple to keep track of -- the playing card suits, you have a lot of flexibility with how you can use them.
Mix n' Match Charts
If you think of a better name let me know, but here's how I think this type of chart could be useful. You have a Mysterious Stone in your dungeon that does things to poor adventurers. You need some effects. The most straightforward way is to custom make a chart for the Stone. And then you make a new chart for every new Stone. Another approach would be to try to abstract out all possible effects into a more generative type of chart, something like my Spell-Like Effects Spur. But it's hard to abstract, and those charts still leave some of the generative burden on your shoulders. Mix n' Match charts are somewhere in between.
First, make some charts of broad categories (like the four magical effect types).
Next, make sure those charts have fairly uniform distribution in the type of results (not Stepped Charts) and a simple way to label them (playing card suits).
Then, pick and choose the effects from your various charts for your Mysterious Stone.
If the effect isn't really variable you just label the Stone in the way the 1e DMG suggested labeling artifacts. We'll give our Stone effects A♣ and 2♦. If the effect is variable you can construct your chart thus:
If we add a fifth suit of weird effects, say Jokers §, then you could even roll d100 to give a completely random type of effect. Like this:
So, as long as we craft some charts with care, it seems like we can use them for a long time, vertically or horizontally, designing adventures as well as on the fly at the table.
Here is my chart of Minor Malevolent Effects.
Here are the cards to use at the table when ill-starred adventurers are struck with these effects.
I plan to make the other four charts (including the jokers) and post them, but let me know what you think, both about this Mix n' Match way of using charts and the specific minor malevolent effects.