demonmagus
spamming my way to the top...
are pearl danios too silvery? albino kribs would look good - although they have some colour to them it sticks out even more 
So betta, contrast and planted invert are the top three now.Contrast tank:
Might have a bit of trouble selecting many types of fish, but would look neat, albino fish freak me out tbh.
Brackish:
Would be lovely but you don't have a lot of options. Marine?
Goldfish!:
Neat, but you couldn't keep many, just 2 fancies!
Cichlids:
Good, but you wouldn't be able to keep a lot of the bigger more colorful species e.g. mbuna.
Invertibrates:
Would be interesting, like the idea, but how about some rasboras to occupy mid-upper levels? Would be sort of boring without. Love the idea of planted w/ inverts and maybe some harlequins above.
Neon tetra:
Not a fan of them.
Plants:
See inverts. Love planted tanks, but why just plants?
Clear:
Not a lot of options, but interesting.
Specialty:
Could be interesting.
Betta:
You could do a sorority of about 20 females easily, would love this idea! I think you could get away making a planted tank w/ decorations like that of a thai rice paddie - place. Lots of mosses, etc, think it would look fantastic, also you could add some cories and get away with maybe 15 females. Favorite option IMHO.
Underwater city:
Meh, not a big fan of it.
o.0:
Odd fish like blind cave tetras (no eyes) weird catfishes etc? Or planted biotypes like the amazon, asia
Color Specific:
Blah... boring...
Reverse contrast:
Dunno.
Elephant nose:
Don't know anything about them.
And betta gets another vote!female bettas are quite colorful as well, could try planted female betta sorrority, with some otos, and if its heavely planted enough, perhaps even some inverts could work too in heavily planted, and escape getting chomped, or you might get lucky and get friendly female bettas who'll leave shrimps alone xDD

how about a contrast tank with a few female betta in to, white/cream of course to fit in with the theme?
Betta:
Would a betta have too much room in a 40 gal?Not sure if I want to use the entire tank for one fish.
wait a minute, has the tank changed size, sure it was a 40 gal before
i got confused cause it said 29 gal first, then others said 40 gal
Yeah, someone pointed out I had the size wrong.Betta:
Would a betta have too much room in a 40 gal?Not sure if I want to use the entire tank for one fish.
it was originally 40 as you can see from the first post, which would of been great for what others are reccommending, with 29 gal you won't have as much choice on the fish especially if shoals are included