Given the tank size, bigger fish can't be too big. So a few suggestions for you to look at when you go to a fish shop.
These are fish that I have owned during the last 20 years, and are fine in water of hardness 7.4 dH:
Honey gourami,
Trichogaster chuna. Peaceful for a gourami and is small enough. 1 male 2 females would be suitable for your tank. Only 1 male as they are territorial. Comes in a few colours - natural (tan male, silver grey female), yellow and red. Natural are quite easy to distinguish the gender, yellows are a bit harder but I can give you a few pointers if you decide on these fish, red are almost impossible to tell apart.
The slightly larger dwarf gourami comes with built in health issues and are best avoided.
Apistogrammas. There are several species, some of which need very soft water. These are colourful bottom dwelling fish, though they also swim mid water. The two most common species are also ones that do well in harder water - cockatoo cichlid,
Apistogramma cacatuoides and agassizi's cichlid
A. agassizzi. Both of these come in a few colour variations, though of course the brightest, most selectively bred ones are the most expensive.
There is a third apisto; the umbrella cichlid,
A. borellii is not as common in shops, but the male is blue rather than yellow-orange.
These apistos are all fine as a male/female pair or 1m 2f trio.
Peacock goby/gudgeon
Tateundina ocellicauda. Another bottom dweller, but don't let that put you off. Again, 1 male 2 females. I have 5 of these fish in my 180 litre, 2m 3f. And even in a tank with a 107 x 45 cm footprint, the males size up to each other, so for your tank definitely only 1 male.
Other members will have their suggestions for larger, 'centrepiece' fish.
For small shoalers, the problem you will have is reducing the possibilities to a sensible length list

In the fish profiles in the menu at the top of the page, most of the smaller tetras would be suitable - except serpae tetras which are nasty nippy things if you chose gouramis.
Cherry barbs
Harlequin rasboras, Trigonostigma heteromorpha and their closely related lookalikes, Trigonostigma espei (slender rasbora, lambchop rasbora, espe's rabora) and Trigonostigma hengeli (copper rasbora, porkchop rasbora, hengel's rasbora). The last two have quite a few common names each!
Dwarf pencilfish, Nannostomus marginatus
And even the ricefish I have, Oryzias woworae.
There are few fish of the genus Pseudomugil that would be suitable, but check up on which ones are in the shops as some species need hard water. Species that would be OK at 7.4 dH include P. signifer and P. gertrudae, but not P. furcatus, which needs hard water.
That's enough fish for now
