Some neat non-Nepenthes plants that I own are the Cycads "dinosaur tree ferns" some people call them since they are estimated to have been around relatively unevolved since at least the Cretaceous Period. They form hard fern like fronds on the tops of very scaly trunks. they take forever to grow and create a sizeable trunk but they survive almost anything. If you get one buy the biggest trunked one you can find (ignore the leaves) bring it home and cut off all the leaves keep it hot, bright and humid and you will get a whole new set of leaves that should be much larger and better looking, when growth stops for a month or two then remove all the leaves again to instigate new flush of leaves All the while feeding with a balanced fertilizer.
Aristolochia or "pipe vines" are a group of 500 or so species of vigorous climbing vines of mostly heart shaped leaves and amazing flowers which resemble Nepenthes pitchers ranging from 1" to 18" in diameter! Easy to train on a trellis indoors or in apot with 3 bamboo stakes stied in a "teepee" shape.
A cousin to the Aristolochia are the Asarum or "wild ginger" which is in the order Aristolochiae and resembles a cross between a tubular masedvallia orchid flower and a rafflesia flower. These look like very large Utricularia reniformis with big flat kidney shaped leaves on the top of a stiff petiole. I have several of these are they are easy plants ranging from tiny to rather large. One of the smallest but prettiest is Asarum maximum or "green panda". If mine was flowering I'd show it to you.
Aroids such as Amorphophallus, Dracunculus, Sauromastum or "Titan Arums, Voodoo Lilys, Corpse Flower, Devils Tongue" all make a single leaf shaped like a palm tree and eventually flowers which range from about 2 feet to 10 over feet in the largest species! Unfortunately the flower scent of these plants is said to resemble a rotting carcass for a couple days hence the name Corpse Flower! None of mine have flowered this year so I can't vouch for the scent. Arisaema or Jack in the Pulpits, Calla Lilies, Alocasia/sheild plants are also aroids and are pretty neat (and don't stink).
The weirder the better!
Edit: Duh, how could I forget? I love the bizzare shapes of the Pleurothallid alliance orchids such as the genus': Dracula, Masdevallia, Dryadella, Porroglossum, Restrepia, Pleurothallis, etc. these orchids are all quite small (not the Draculas or Masdevallia so much but the others generally stay under 3-4 inches tall), epiphytic and from cool montane forests, perfect companions for highland Neps. Pleurothallids flower almost continuously as long as they're happy and fertilized. The Pleurothallid orchids somewhat resemble the weird shapes of Utricularia in both flower and leaf shape. Bulbophyllums are very awesome as far as warm growing orchids. Slipper orchids like Paphieopedilum and Phragmepedium are awesome too and quite easy except the flower so rarely, thankfully their blooms last for months on end!