[Kubla]

You should be good for a bit more stock. Depending on your filter system you could probably add a few frogs. Are you familiar with AQ ADVISER? It's a stocking calculator. It's not perfect but it's a great starting point. Be careful with plecos. The most common smaller species are the different bristlenose and most recommend a larger tank than 10 gallons

 

[Marcos Costa]

I believe that nothing else fits in your aquarium, you have to take into account the decoration too.

 

[ustabefast]

I don't think you have room for an algae eating fish, unless perhaps an otocinclus catfish, but they can be difficult to keep alive without supplemental feeding.
An Amano shrimp could be an option, or even a few ghost shrimp.

 

[Kubla]

What kind of filter do you have? How heavily planted is the tank? Otocinclus would be fine except it's usually recommended to keep them in groups of 6 or more. Six is way too many for your tank.