These are great, Seneca! Here are some points to keep in mind:

The overall space the icons takes up from one to the next should be relatively the same. You want to think of there being an invisible square or circle and the entire composition of each icon should somewhat fit that shape.

The thought bubble is kind of a wonky shape, maybe move the 2 bubbles to the left more so it creates a more cohesive shape.

I think the profile of the head could use a little more humanistic features like the nose and indent above the lips.

All icons should share a similar quality. Whether it is the color, style and aesthetic, or subject matter. some have one accent color, while others have more. Is there a way to have navy be the base color and then 2 accent colors per?

Last thing, the one in the top right is very fun, but it's the only one that relies on something chopping or stopping it (the rainbow) all others show the form in its entirety. Does that make sense?

Some small tweaks and you're there!