Interesting. I've yet to see anything fitting this exact description myself. The two small annoyances I have encountered would be...

1 - Small blob like things
These I have encountered more than once. They usually latch on to you and are hard to remove. Sometimes they target me when flying...as far as I can tell they do not have any features, just dark blobs.

2 - Little spider monkey things. I say spider monkey because they are small, agile and have really long tails. These jump and latch right on to my face. Have only seen them a few times, once I made a game out of it. It would jump to latch on to my face and I would catch it and throw it before it could, then it would sprint back to me and I would do it again. Was kind of (fun?) I guess these could be similar to your gremlin description but they are really small, like under 12 inches and didn't really have the same features as your drawing.

I also have had a few (snakes?) latch on to the back of my head. They make a weird "pop" when you pull them off and you feel light headed/dizzy. I used to think they were a hand/arm grabbing my head from behind until I learned how to pull them off (used to happen a lot when I first started intentional OOB/AP) haven't seen one in a long time.

I also see these strange "clear/transparent" things. Usually it's when I am first leaving my body. They seem completely harmless, it's almost like they are trying to materialize but can't quite do it. They usually try to charge into me, kind of like a bird trying to fly through a closed window. They bang against me a few times and I just leave. Once one of them was very large, almost like a small human, might have something to do with shifting dimensions/etc but that's out of my league to say at this time.