Am I under/over stocked?

I have a 300 liter tank; fairly planted. I have 11 neons, 9 rummynose, 6 lemon tetras, 6 bronze corys, 5 cherry shrimp and a nerite snail. Thinking if i could add more. Suggestions please. Thanks..
PS: I've attached a picture.

Id add more rummy nose tetra up to 15 20 total. Rummy nose are really tight shoalers and will look even better in a larger shoal.
Could always add a pair of dwarf cichlid like apistogramma or a group of bolivian rams.
If you wanted to fill out the top of your tank you could get some hatchet fish, marbled stay smaller than silver. .
If one wanted another shoaling fish different then tetras one could get a group of pencil fish or rasboras

I would up all your tetra schools, but rummynose specifically because they like larger groups, and I would get TONS more corries, since you have bronze (c.aeneus) you can get albinos or green corries(not emeralds) just make sure they are Aeneus. I would have at the very least 20 corries in that tank.
i would also get a trio or 2 trios of pearl gouramis.
what is the temp at?

Nice tank, I would suggest filling it up more, the water level looks a bit low.

I would suggest 12 of each. (12 neon tetras, 12 rummy nose tetras, 12 lemon tetras, and 12 Cory's.)

They feel more comfortable in large groups.

You have considerable space left, and I agree with suggestions to increase the various groups. This really does make a vast difference to fish health, and that means more enjoyment for you.

Beyond that, ytou have space for additional species, several good suggestions have been posted above. We are all assuming water is on the soft side (GH).

When the floating plants have spread to basically cover the surface, these fish will be much more relaxed and more colourful than they are even now.

I agree with everyone else. Definitely up the groups you already have