These are the best photos I can capture considering the bug was moving pretty quickly. I really hope these don't pose any threats to my plants.

That is going to be a tough one--too blurry. Possibly a weevil if nearby vegetation is getting notched leaves. Place one or more of the insects in the refrigerator and photograph when still.

Thanks Larry, these little buggers are very quick and nimble, so I squash it in a moment of panic when it attempted to crawl onto my hand. If I spot one in future, I'll probably bag it and put the whole tray into the freezer - that way I can get a better close up shot once it's frozen.

For this type of insect, a small, clear container, plastic or glass, and its lid can be effective as a trap. Once the inverted container is over the insect, tilting it may induce the bug to crawl up the side, allowing placement of the lid. If capturing in mid-air on a plant, use jar & lid as a pair of cymbals. These methods avoid handling the insect, although it does not appear to be of the biting or stinging type.

Hi again Bernard!

I found a similar looking insect when I was watering my succulents as well! They are also in a variation of Al's gritty mix. This is the photo I managed to take, do you think it's the same insect? It's very tiny and moves very fast, greyish.

I'm getting more concerned now. I've been watering my succulents more frequently now due to the warmer weather, and last night I found them in almost all of my plants watering tray!!

It's funny that they only stay on the tray.

I've dumped one tray in a baggie and froze it, not very helpful snapping pics when it's dead. It's really too small.

I tried snapping more on another one that is under another plant.

I tried to zoom in and make a close up

I hope these aren't similar to mealy bugs or pose harmful threats to my plants.

Larry! I think we are speculating it to be Springtails.. we're seeing a huge uprise in the NorthEast here. Thanks so much for your help though.

The primary springtail behavior, that is springing when disturbed, was not mentioned, perhaps you did not see it with your insects. Should be easy enough to determine. Your pictures do look like springtails in size and shape.