Assuming tank dimensions are 38cm x 38 x 43 high, stock this tank much as you would a 30/35cm cube tank - fish occupy floor footprint more so than height footprint, with fish in mind I wish this tank had been designed as 43 wide & 38 high, it would allow more options for the fishkeeper & more comfort for most fish
Bumble bee gobies - I've included the Seriously Fish link for the species name these fish frequently ship under
regardless of actual species & this is where challenges in their long term maintenance lie, so do your research; my opinion is that this tank lacks sufficient footprint for any bumble bee gobies, they really prefer to be kept in groups but also display territorial aggression within the group which is why a larger tank (bottom) footprint is needed, I'd consider a 60cm x 40/45cm to be the minimum dimensions
Galaxy rasborasu - again I suggest reading the SF profile, you might manage to keep these long term in this tank size (45 x 30cm footprint is minimum recommended) but some of the other micro rasbora species would likely be a better fit
(I agree on the minimum 20 group size but you'd want the tank well established before adding this many ... they also appear more comfortable in low flow, optimum water quality environs)
Betta would certainly be comfortable in this tank (depending on flow) but some are avid shrimp hunters so it's best to establish shrimp population first with lots of plant cover
Pygmy corydoras - as you may be expecting by now, 45 x 30cm footprint, but they are fairly adaptable so 6-10 would likely manage long term, just less
zooming space for them
Otocinlus - I feel this tank is too small for a group of (minimum) 6 Oto's as a long term home, I'd do snails instead
Of course many shops will say, 2-3 Oto's is fine in this tank size, & they will survive, but you won't see the behaviours that make them such an enjoyable fish to keep
If your local shop accepts fish returns/trades it's much easier to "try out" various species to find those that will do best in your tank