This really depends on the size of your tank and the type of lights you have.
If this is the 10 gallon you were talking about in your earlier post, you'll be really limited, particularly if you have the standard 15 watt bulb.
For plants, java moss is awesome. Lay it on the substrate and sprinkle gravel over it lightly to hold it down, or lay it in a single layer on a rock and hold it there with a hair net, like the lunchlady wears, or stitch it to driftwood or pvc pipe or flowerpots or needlework grid with 2 lb test fishing line. Over time it will grow to cover what it's on.
Anubias are expensive, but look awesome. They also can be tied to rocks and driftwood. They grow exceedingly slowly, but they don't mind low light (which is what you have) and are hard to kill. Just make sure you don't bury the rhizome.
Java fern is yet another one that gets the same sort of treatment, and it's less expensive.
Other plants that can work in a small tank in low light - cryptocoryne wendetii (look for green, red, bronze, tropica, and mi oya crypts.), Amazon Compacta Sword. Brazillian pennywort, Hygrophila corymbosa Siamensis (Grows just fine, not sure how much I like how it looks, though). Wisteria (Hygrophila difformis) - though this can take a 10 gallon over if you don't trim it. Fortunately it grows slowly under low light.
I've had fair succsess with Rotala indica in a 10 gallon tank under a 15 watt bulb. Not great success, but it seems to be surviving.
I've also done alright with Cabomba carolinia, but I know of other folks who haven't.
I'd stay away from nymphea spp. (too big), and Eleoda - unless you are a real scissor enthusiast - grows like mad and can get up to 5' long. Way too big for 10 gallons.
For Fish, Ottos and Pitbull Plecos are really your only algae eating options, vertebrate wise. Other algae eaters include amanao, red cherry, and crystal red shrimp. If you have plants, you will have snails unless you are really careful to kill the snails and eggs before you put the plants in the tank. Frankly, I wouldn't add any snail other than maybe Malaysian Trupet Snails to a tank on purpose, and then only if I had a sand bottom.
Bottom feeders: Small Cories only - C. hasbrosus, hastatus, pygmaeus, guapore, and panda are all good. There are also some less well known catfish that will work in a 10 gallon tank, but you're not likely to see them. Moth Catfish are one of them. Oil Cats (Tatia perugiae (sp?)) might work in a 10 gallon, but it would have to be a species tank with mo more than 4.
Schooling fish: up to 10 of any of the small tetras or rasboras or the very smallest danios - even more of some (up to 15 neons, for instance, or 20 spotted pygmy rasboras) - Neons, Ember tetras, Glo Lights, Black Neons, Flame Tetras (VoRios), Green Neons, Dawn Tetras, Silvertips, Harlequin Rasboras, Rummynose (careful with these - hard to keep stable water conditions in a 10 gallon), Danio choprae, Phoenix rasboras, exlamation point rasboras. Threadfin rainbows also work, as would scarlet badis (dario dario).
There are no barbs, loaches, or goldfish that will survive long in a 10 gallon tank. Not that you're likley to see.
Livebearers - Males or Females - not both unless you want to be overrun with fry. Guppies and Endlers are the ones you'll see. Some of the Gooedids will work, but those you'll have to get through their associations if you want them.
Anabantids-Bettas are the classic: one male or 6 females (no more, no less) in a 10 gallon tank.
Honey Dwarf Gouramis would work - up to 3, the same for sparkling gourmais. Also licorice gouramis - but these are a real chore to keep - more sensitive than rummynoses, and only take live food.
Bumblebee gobies - these are brackish, and there really aren't any other brackish fish that are happy in a 10 gallon, so this would be a species tank.
The only other fish I can think of off the top of my head that would be at home in a 10 gallon would be the Dwarf Puffer. You might be able to get as many as 3 in there (one male, 2 females). I was successfully dissuaded from doing just this by finding a beautiful white delta tailed male betta, but if you go with puffers, they'll solve any snail problem you might have (and give you the problem of raising enough snails to keep their beaks ground down.)
I recommend googling aquacaping and viewing the tanks on the AGA aquascaping contest, in the small category to get ideas for livestock.