Hi, in a (roughly) 40g tank you will be able to have quite a few more fish than you have listed and in some cases you need it
So for starters bump up your danios to at least 8 in total, I believe that the golden zebras are the same species but not 100% lots of new danio species coming through now and might be different. Although a small change it will be a difference to the fish in there. Ill leave it to your choice though. Khulli loaches - need to be all the same type as again are all the same type of fish and need to be in a group of 6 at least. Platies are fine in 4 but watch for the amount of fry you get if you already have some be prepared to find an LFS that will take them off your hand. Pleco will be fine very nice choice
- Snails, if you want one that wont reproduce that easily get an assasin snail that way if you get any pest snails it will sort them out good and proper and as for shrimp go for any you like really tons of colours available now, red, blue, green, gold, white, bumble bee any really unless you want to go for bigger ones like ammano shrimp but you dont have any fish that pose a massive threat to the shrimps.
So just to recap I would do -
2 Banded Gourami
10 Zebra Danio
4 Platies + fry
8 Khuli Loaches
1 Starlight Plec
10 Cherry Shrimp (as example)
3 Assasin Snails
and if those are the fish you want that would be a very nice 40 gallon tank IMO
Just one thought to add I have upped numbers of existing fish rather than adding or suggesting new species as things like your danio and loaches are going to look much better in bigger schools and the fish will like being in bigger numbers and give you more natural and active behaviour than if they were in smaller numbers.
Wills