What to use as general info node in scene?

I need to place a large number of invisible info nodes in the scene, for my scripts (not an AI player though) to find and inspect, and base various info display and decisions on. I only need to read the position and some string from them, so apart from that they should be as lightweight as possible; I will be using quite a lot of them.

But which kind of object should I use, if I want to avoid messing with the enginge code? I know it's an ugly hack to misuse other classes for this, but it would really solve my problem in an easy way.

My first instinct was to use waypoint markers or similar, but it turns out that the "containerSearch*" doesn't se them, no matter what mask I use, unless I'm in world edit mode.

Triggers do work, but I assume they would create quite a bit of unnecessary load if I've got 500 of those lying about my level. Or does it all disappear if I set the tick to 0?

Can static shapes be made invisibleto the renderer (or have no mesh at all) but still be accessible to "containerSearch*" and friends?

Or is there simply no suitable object type, and I'll have to create one in C, or use C code to detect the existing ones?