Depending on how low or high tech you want to go, there is a range of plants you could choose.
For a low tech tank and in a tank of that size, I would go for some java fern (windelov and the narrow leaf varieties are nice), smaller species of anubias, and maybe even some bolbitis or crypts.
If you went that route, all you would really require would be an inert substrate with some gravel tabs for the crypts. You could probably get away with using only natural light, as all of these plants have very low light requirements. Maybe dosing once or twice a week with a comprehensive fertiliser would be necessary but otherwise I only dose if I notice deficiencies.
Otherwise you could go the whole hog and use aquasoil or just plain old garden soil and have a set-up with a lot of stem plants and floaters. This would however, need more maintenance and higher light due to the growth rate and requirements of such plants. You would also have to do more testing initially as some soil substrates can leech ammonia and other nasties out into the water column. However, once mature these tanks tend to be very stable as floaters and stems are essentially nutrient sponges and will take up a considerable amount of ammonia and nitrates from the water column.
I have Egeria Densa in nearly all of my fish homes. It's ridiculously low maintenance and quick growing. Really the only thing that you ever have to do with it is break off the new shoots (if you don't, the mother "strand" will start to get raggedy looking, in my experience) and I, personally, absolutely love the look and sway of it. I know it's nothing too exciting, but I love it.
Also, Java Fern, Ludwigia, Anubias, Crypts and mosses.
i just started a 2 gallon betta jar, so far no fishy but it's got about five stalks each of water wisteria, water primrose, some 2-3 inch tall anubias clones, and a big tall dracenia sanderia that's rooted in the middle and blooms out over the surface of the water. i'm thinking of putting a java fern in next.
That's alright, you know?
One of my favorite opinions is that plants, just like animals and people, have to be compatible with their living companions. I know it's far from scientific, but I'm a strange child, and it's the way I feel.
If you've tried one a few times and had no luck, just try a different one. Eventually, you'll probably find one that likes your touch.
Out of curiosity, what kinds of plants have you tried, and what other lives share your home?
i just started a 2 gallon betta jar, so far no fishy but it's got about five stalks each of water wisteria, water primrose, some 2-3 inch tall anubias clones, and a big tall dracenia sanderia that's rooted in the middle and blooms out over the surface of the water. i'm thinking of putting a java fern in next.